Маленькая победоносная война для NASA

[ronatu]

Вот-вот. Цели становятся все реальнее...

[Димитър]

Не подходит Cruithne как первую цель! ХС = 13.510 км/сек!  
Вы списк посмотрите:
На первое место -  1991 VG, ХС = 3.998 км/сек. Да вот Н (абс. величина) = 28.5m - это всего лишь камень диаметром в несколько метров! Не нравится мне.
С 8 до 10 места: 2003 SM84 - 4.222 км/сек, 2001J142 - 4.225 км/сек, 2000AE205 - 4.247 км/сек/ H у них - 23 - 23.5m - диаметр уже несколько десятков метров. А ХС больше, чем у первого всего-то на 224 - 249 м/с!
Дальше - Итокава. ХС = 4.632 - на 634 м/с больше, чем у первого, но зато астероид уже приличный - 535

[Олигарх]

Не подходит Cruithne как первую цель! ХС = 13.510 км/сек!  
Вы списк посмотрите:
На первое место -  1991 VG, ХС = 3.998 км/сек. Да вот Н (абс. величина) = 28.5m - это всего лишь камень диаметром в несколько метров! Не нравится мне.
С 8 до 10 места: 2003 SM84 - 4.222 км/сек, 2001J142 - 4.225 км/сек, 2000AE205 - 4.247 км/сек/ H у них - 23 - 23.5m - диаметр уже несколько десятков метров. А ХС больше, чем у первого всего-то на 224 - 249 м/с!
Дальше - Итокава. ХС = 4.632 - на 634 м/с больше, чем у первого, но зато астероид уже приличный - 535

[Oleg]

Или прямо на (433) Eros ? ХС = 6.069 , размеры - 13

[Димитър]

Но на мой взгляд, пилотируемому КК вообще не нужно зависать над астероидам! И следовательно, уравнивать скорость! Не понимаю я этой всеобще зацикленности на том, чтобы человек лично прикоснулся ...
Прикоснуться, взять образцы сможет намного дешевле и безопаснее автомат.

А на хорошей девушки Вы тоже захотели бы тоько взглянуть, а не е-е-е... лично прикоснуться ?    Только не говорите, что здесь не тот случай!  :wink:

Олегу:
Вообще-то я предлагал полететь к астероиду 1999 JU3: ХС = 4.651, Н = 19.4 (те же размеры и ХС, как у Итокава) или к 2001 US16: ХС = 4.428, Н = 20.2 (Немножко поменьше, но зато и ХС на 200 м/с меньше). Меня эти два объекта вполне устраивают.

[Димитър]

Помогите разобраться!
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

Не понимаю, что они включают в "Delta-v for transferring from low-Earth orbit to rendezvous" ? Выход на орбиту астероида? С возвращением на траекторию к Земли или без?

[ronatu]

Помогите разобраться!
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

Не понимаю, что они включают в "Delta-v for transferring from low-Earth orbit to rendezvous" ? Выход на орбиту астероида? С возвращением на траекторию к Земли или без?

Delta-v is computed following the approach described by Shoemaker and Helin (1978), Earth-approaching asteroids as targets for exploration, NASA CP-2053, pp. 245-256.

[ronatu]

I love this!!

http://cfa-www.harvard.edu/iau/Animations/Inner.gif

[ronatu]

Помогите разобраться!
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

Не понимаю, что они включают в "Delta-v for transferring from low-Earth orbit to rendezvous" ? Выход на орбиту астероида? С возвращением на траекторию к Земли или без?

delta-v это НЕ есть характеристическая скорость.
В лучшем случае ее половина.
http://en.wikipedia.org/wiki/Delta-v

[Димитър]

delta-v это НЕ есть характеристическая скорость.
В лучшем случае ее половина.
http://en.wikipedia.org/wiki/Delta-v

Вы не поняли. Смотрите хорошо в Википедию.  :wink:

[ronatu]

delta-v это НЕ есть характеристическая скорость.
В лучшем случае ее половина.
http://en.wikipedia.org/wiki/Delta-v

Вы не поняли. Смотрите хорошо в Википедию.  :wink:

Delta-v budget (or velocity change budget) is a term used in astrodynamics and aerospace industry for velocity change (or delta-v) requirements for the various propulsive tasks and orbital maneuvers over phases of the space mission.

Может я чего-нибудь не понял но в случае с астероидами это был "билет в один конец"? :roll:

[Олигарх]

Помогите разобраться!
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

Не понимаю, что они включают в "Delta-v for transferring from low-Earth orbit to rendezvous" ? Выход на орбиту астероида? С возвращением на траекторию к Земли или без?

Да, похоже, билет в одну сторону.
С этой страницы:
Delta-v for spacecraft rendezvous with all known near-Earth asteroids (q < 1.3 AU)
Delta-v is computed following the approach described by Shoemaker and Helin (1978),
Earth-approaching asteroids as targets for exploration, NASA CP-2053, pp. 245-256.

Last updated Mon Mar 12 09:31:41 PDT 2007
Source for NEA orbits: Minor Planet Center
http://cfa-www.harvard.edu/iau/lists/Atens.html
http://cfa-www.harvard.edu/iau/lists/Apollos.html
http://cfa-www.harvard.edu/iau/lists/Amors.html

N = 4521

For comparison, delta-v for transferring from low-Earth orbit to rendezvous
with the Moon and Mars:
   Moon: 6.0 km/s
   Mars: 6.3 km/s

Мне не удалось найти описание подхода (approach), предложенного Shoemaker и Helin.
Но для Луны delta-v for transferring from low-Earth orbit to rendezvous
with the Moon:
   Moon: 6.0 km/s
Для отлета с LEO к Луне нужно около 3,2 км/с. Для торможения, выхода на орбиту вокруг Луны около 0,9 км/с. И для посадки (rendezvous около 1,9 км/с.
Так и набралось 6.0 км/c. для Луны.

Но для Марса должно быть больше, чем 6.3 км/с. ... !

[Димитър]

For comparison, delta-v for transferring from low-Earth orbit to rendezvous
with the Moon and Mars:
   Moon: 6.0 km/s
   Mars: 6.3 km/s
Мне не удалось найти описание подхода (approach), предложенного Shoemaker и Helin.
Но для Луны delta-v for transferring from low-Earth orbit to rendezvous
with the Moon:
   Moon: 6.0 km/s
Для отлета с LEO к Луне нужно около 3,2 км/с. Для торможения, выхода на орбиту вокруг Луны около 0,9 км/с. И для посадки (rendezvous около 1,9 км/с.
Так и набралось 6.0 км/c. для Луны.

Но для Марса должно быть больше, чем 6.3 км/с. ... !

Вот именно! То, что подходит для Луны, не подходит для Марса...  :?

[Олигарх]

I love this!!

http://cfa-www.harvard.edu/iau/Animations/Inner.gif

The Space Review: Asteroid missions: be patient, or bring lotsa gas        

http://www.thespacereview.com/article/838/1

       
      Asteroid missions: be patient, or bring lotsa gas
      by Tom Hill
      Monday, March 26, 2007
     
 There's been an upsurge in interest in crewed missions to visit a near
      Earth asteroid. The prospects of new spacecraft, along with the more
      distant, yet still possible, larger rockets to push the new craft to the
      Moon, Mars, and beyond have fired the imaginations of scientists and
      laymen alike.
Many say that a near Earth asteroid is the next logical step
      after the United States' return to the Moon, sometime before 2020. Others
      say that an asteroid mission could be taken even before the return to the
      Moon. They say such a mission could alleviate the "been there, done that"
      feeling which some detractors love to bring up any time the Vision for
      Space Exploration is mentioned.

      The interest has led to a number of articles in space trade news (such as
      this SPACE.com article) and even in mainstream newspapers such as USA
      Today, where the classic but overstated "huge asteroid impact" graphic was
      placed above the fold on page 1, and missions to asteroids were part of
      the discussion within. Crewed asteroid missions also received a short
      mention in NASA's report to Congress on the NEO threat.
           
      An asteroid mission is an exciting prospect. Its allure includes the
      possibility of using less propellants than a lunar landing mission and not
      requiring the development a separate landing vehicle. The idea of
      exploring new territory is always enticing and cannot be overlooked, while
      mission timelines are possible that are on the order of an extended lunar
      stay, serving as stepping-stones to much longer Mars missions.

      It turns out that two of the criteria used to argue for an asteroid
      mission—low propellant use and short timelines—are linked to each other
      through the mathematical dance of orbit mechanics and the rocket equation.

      Unfortunately, asteroids that have the potential for short, low-fuel
      missions are extremely rare. In an ironic twist, the same attributes that
      make them good candidates for such a mission contribute to the rarity of
      such an opportunity.

      Mission overview

      Recent articles have focused on asteroid missions where the explorers
      don't have to travel any farther than a few times father from the Earth
      than the Moon, so those missions are the focus of this study. Other
      mission scenarios are possible, such as the Gaiashield mission proposed by
      Zubrin in Entering Space, but that mission in particular does not claim to
      hold journey durations or distances low.

      Missions to near Earth asteroids working to take advantage of a pass close
      to Earth essentially meet an asteroid at the fringe of Earth's
      gravitational influence. The craft travels out to the rendezvous point,
      taking between days and weeks depending on the propellant budget and
      trajectory chosen, and then adjusts its path to drift with the space rock
      within Earth's gravitational well. This period of time is called the
      proximity operations period. When the asteroid reaches the opposite side
      of Earth's sphere of influence, the craft fires its engines again to
      return to Earth.

      Orbit mechanics

The mission sounds easy, right? Theoretically, as far as space missions go, it is easy.
!!! Finding a candidate asteroid that supports such a mission is not.

Asteroids, like the planets or any other object traveling through
      space, follow the laws of orbital mechanics in their paths, and those laws
      complicate mission planning.

      Six terms are necessary to define an orbit and an object's place within
      it. When describing an orbit using classic Keplerian elements, there are
      three major terms that affect the shape of the orbit:
inclination, eccentricity, and semi-major axis.

Another consideration is the phasing of the Earth in its orbit with the asteroid in question.

      Inclination describes the angle that the target orbital plane makes in
      comparison to another plane and is typically measured in degrees. For
      planetary bodies, inclination is defined as the angle between the orbit in
      question and Earth's orbital plane. Earth's orbital plane is also called
      the ecliptic.
Asteroids that pass near Earth are inclined to its orbital
      plane by some amount, and that amount varies greatly.
Objects in the initial data gathered for this survey had inclination values between 0.1
      and 63 degrees. While an orbit's inclination is not related to the size of
      that orbit, inclination plays a large role in suitability for a mission
      profile described here.
An asteroid in an orbit with any measurable
      inclination compared to the ecliptic will only be capable of a truly close
      approach to Earth when it crosses the ecliptic plane, a point also known
      as the nodal crossing.
Even on these close approaches, the differential
      speed of the asteroid compared to Earth is approximately 500 meters per
      second for each degree of inclination of the asteroid's orbit.
           
      Eccentricity describes the shape of an orbit, and it is a dimensionless
      quantity. At the theoretical yet never achieved eccentricity of zero, an
      object is in a perfectly circular orbit around its parent body.
Increasing
      eccentricity describes a more elliptical orbit, with the near point of the
      orbit growing closer to the parent body and the far point growing more
      distant, up through an eccentricity value of 1. An eccentricity of 1,
      another theoretical value, describes an infinite ellipse also called a
      parabola.
The infinite varieties of ellipses available create some
      interesting situations, although very few produce orbits that are
      compatible with a low delta-v mission to an asteroid. All but the lowest
      eccentricities can create a situation where the orbit of the target
      asteroid crosses Earth's orbit at an angle that drives delta-vs to an
      unacceptably large value.
!!! The missions that are the focus of this paper
      require the right balance of eccentricity and the next term, semi-major
      axis.

      While eccentricity specifies the shape of an orbit, its semi-major axis,
      expressed in units of length, relates to the amount of time it takes for
      an object to orbit its parent. The orbits of two objects with the same
      semi-major axis but different eccentricities can look very different, but
      take the same amount of time to make one circuit around a parent body.
      Objects with a semi-major axis much smaller or larger than that of Earth
      can cross Earth's orbit, but doing so requires a relatively high
      eccentricity and these objects rapidly fall out of consideration for low
      delta-v missions.

      Phasing is not an orbital parameter per se, but it requires mention here.
      Any asteroid that makes a close approach to Earth will, in all likelihood,
      make another pass at some time in the future. The closer the orbital
      period is to Earth's, the more time between close approaches there will
      be. The same effect can be seen in the launch windows that allow missions
      to other planets. The outer planets, having orbital periods much greater
      than Earth's, regularly align for a minimum-energy launch window
      approximately once each Earth year. Mars, with an orbital period much
      closer to that of Earth, aligns for a mission only once every 26 months.
 
      Near Earth asteroids, many with periods even closer to Earth's than Mars,
      can go years between close approaches that would allow the kind of
      missions discussed here.

      Methodology

      The research for this article is easy to duplicate for anyone interested.
      The list of near earth asteroids and their orbital elements (a potentially
      large web page) was downloaded in January of 2007 and saved as a text
      file.
The list was converted into spreadsheet format, and only those
      asteroids with semi-major axes between the arbitrarily-chosen values of .9
      and 1.1 astronomical units (AU) were used for further study.
This smaller
      list (still containing over 300 objects) was then sorted by inclination
      followed by eccentricity, based on an initial assumption that inclination
      would be a larger delta-v cost than inclination for a mission to that
      asteroid.

      The top candidates from the list were then examined using the orbital
      viewer from the JPL NEO office. The viewer contains a disclaimer that it
      is for visualization only, and experience shows that this warning should
      be taken seriously. Due to the basic nature of this research, however, the
      viewer was deemed acceptable.

      Each candidate asteroid was observed in the viewer to find the closest
      approach that was less than 0.02 AU between now and 2100. The date and
      distance were recorded, and this information could be used as a starting
      point for further analysis.

      Early frontrunners

      Three asteroids jumped out as candidates to show the complexities of a
      crewed mission to each.
The first one, 1991 VG, requires a relatively low
      delta-v to enter and exit proximity operations (833 m/s each) and comes
      fairly close to Earth at five lunar radii. The one problem with this
      asteroid is that its close approach doesn't take place until the year
      2068.

If doubling the proximity delta-v is an option, then there's another
      mission opportunity with the asteroid 2000 SG344, which comes within three
      lunar radii in 2028. The tradeoff is a required delta-v of 1686 m/s to
      both enter and exit proximity operations. Nearly doubling delta-v needs
      again opens an opportunity with the asteroid 2001 GP2 in the year 2020.
         
      Hopefully, new discoveries will provide a larger selection of asteroids
      and mission dates that require less energy to visit using the mission
      profile described here.
The particular class of asteroids best suited for
      this type of exploration is underrepresented in the NEO list, because of
      their difficulty to discover. Some of the detection methods described in
      NASA's recent NEO report to Congress would increase the number of such
      asteroids in the database. It is also possible that other candidates will
      make themselves obvious using more exact orbital determination methods on
      the list we currently have. This will remain unknown until someone doing
      research within the area using better tools makes their study public.

      Conclusion

      Asteroid missions are exciting for their daring, their potential for
      scientific return, their ability to help protect the planet, and their
      meaning in humankind's growth into a spacefaring species. Opportunities to
      carry them out while keeping people within Earth's "neighborhood" are not
      common, however, and many of those instances require a lot of propellant
      in order to make the mission happen. This is not necessarily a bad thing.
      The fact remains that it requires a lot of propellant to get anywhere
      interesting in the solar system, and perhaps an asteroid mission will help
      kick-start architectures that will take us to those other destinations.


      Tom Hill is an aerospace engineer and author based in the Washington DC
      area. He worked on this paper during time that he should have spent doing
      his taxes. An expanded version of the work can be found here
http://spacewhatnow.com/id37.html, and it
      includes a deeper description of the methodology, other asteroids
      researched, illustrations of key points, and discussion of a new article
      released after the final version of this summary was complete. He can be
      reached at tom[at]spacewhatnow.com.

Ну что же, все правильно.
Но все проблемы, о которых пишет автор и которые
сводятся к большой ХС для пилотируемого КК, обходятся, если перейти к концепции
кооперативной экспедиции
- космонавты на борту КК
c малой ХС (несколько десятков/сотен м/сек.),
 а их "руки" - отдельно
запускаемые автоматы с большой (2-4-6- км./сек.) ХС.

Тем более, что такой автомат с большой ХС уже создается - Фобос-Грунт!
Этот КА практически готовая платформа для автоматов кооперативной экспедиции

Какова его ХС после выхода на траекторию полета к Марсу?
И если нужна большая ХС, то самое простое - заменить РН Союз-2б на Зенит/Протон ...

[Олигарх]

Помогите разобраться!
http://echo.jpl.nasa.gov/~lance/delta_v/delta_v.rendezvous.html

Не понимаю, что они включают в "Delta-v for transferring from low-Earth orbit to rendezvous" ? Выход на орбиту астероида? С возвращением на траекторию к Земли или без?

Delta-v is computed following the approach described by Shoemaker and Helin (1978), Earth-approaching asteroids as targets for exploration, NASA CP-2053, pp. 245-256.

PICTURE: NASA manned NEO mission needs robot test-15/06/2007-London-Flightglobal.comFlightGlobal
http://www.spacetoday.net/getarticle.php3?id=102297
 
DATE:15/06/07
SOURCE:Flightglobal.com
PICTURE: NASA manned NEO mission needs robot test
By Rob Coppinger
 
A manned mission to a near Earth object (NEO) would require a robotic precursor
mission for safety, according to a NASA Constellation programme office study
obtained by Flight International.

The robotic reconnaissance spacecraft could detect hazards such as satellites of
the asteroid-like NEO and help determine the local gravitational field and the
target object's composition and topography.
Many NEOs, which appear to be solid asteroids, are thought to be very porous and
often just a tumbling collection of debris left over from the solar system's
formation.
A human NEO mission would be the first beyond the orbit of the Moon and is
expected to involve two or three astronauts on a 90 to 120-day flight that would
involve two weeks of close-proximity operations at an asteroid.
The precursor reconnaissance spacecraft would have a visible camera for surface
feature characterisation, a spectrometer for investigation of the NEO's
composition and a laser altimeter for determining topography.

"A robotic mission would be required in order to maximise crew safety and
efficiency of mission operations at any candidate NEO," says the study paper.
Astronauts would reach the NEO using the Orion crew exploration vehicle, which
currently has two variants: Block 1 for missions to the International Space
Station carrying six astronauts and the Block 2 lunar version that will carry a
crew of four.

A NEO Orion variant would have a high-resolution camera for detailed surface
characterisation and optical navigation a lidar system for hazard avoidance,
close proximity operations and detailed topography measurement and a radar for
tomography to provide detailed interior images of the object.

The Orion would also enable astronauts to conduct extra-vehicular activity at
the NEO, to take advantage of human decision-making to rapidly select and move
to sites of interest for sample collection.

The study does not specify how such spacewalks would be undertaken, whether by
tether or untethered manned manoeuvring unit.
The Orion would also deploy small scientific packages that include autonomous or
tele-operated rovers with one or two instruments each.
Other packages could include drilling and excavation equipment, surface anchors
and transponders for the long-term study of NEO orbital motion.
NASA has considered launching a NEO variant of the Orion using its proposed Ares
IV rocket, the existence of which was exclusively revealed by Flight earlier
this year.

[Олигарх]

Но на мой взгляд, пилотируемому КК вообще не нужно зависать над астероидам! И следовательно, уравнивать скорость! Не понимаю я этой всеобще зацикленности на том, чтобы человек лично прикоснулся ...
Прикоснуться, взять образцы сможет намного дешевле и безопаснее автомат.

А на хорошей девушки Вы тоже захотели бы тоько взглянуть, а не е-е-е... лично прикоснуться ?    Только не говорите, что здесь не тот случай!  :wink:

Олегу:
Вообще-то я предлагал полететь к астероиду 1999 JU3: ХС = 4.651, Н = 19.4 (те же размеры и ХС, как у Итокава) или к 2001 US16: ХС = 4.428, Н = 20.2 (Немножко поменьше, но зато и ХС на 200 м/с меньше). Меня эти два объекта вполне устраивают.

Всеобщая зацикленность на том, что  
    destinations for PEOPLE in space include
!!! only sites that people can walk or drive around on.
- Имеет место и на нашем форуме, и во всем мире!
Авторы этой статьи пытаются показать, что это не так.

The Space Review: Destinations for exploration:
                  more than just rocks?      

http://www.thespacereview.com/article/912/1        

      Destinations for exploration: more than just rocks?
      by Dan Lester and Giulio Varsi
      Monday, July 16, 2007

      Human space exploration has traditionally been inspired by ultimate
destinations beyond the Earth and designed to reach them efficiently and safely.
!!! Specifically, these destinations have been bodies in our solar system.

This contribution to The Space Review proposes that, as we enter
      the 21st century and the sixth decade of modern space exploration,
!!  a fresh analysis be undertaken of the value of different classes of
      destinations—including specifically locations
!!! not characterized by solid materials (rocks, ices, "soils") or gravity.

We consider whether priorities of similar worth could then be pursued on the basis
of the half-century of advances in technology and space exploration experiences.

      In many respects, free space destinations such as Earth and planetary
      orbits and, specifically, the Lagrange points may have
!!! more value than
      planetary surfaces for investigating certain important aspects of our
      place in the Universe.
In what respects is this !!!! traditional focus on rocky
      surfaces and gravity strategically driven, and in what respects is it just
      moot repetition of the past?

Certainly our national goals for space exploration involve more than just science.
However, a large amount of the science we want to do in space has
!!! little need for surface locations and, in fact,
!!! would benefit by not relying on them at all.
           
      A thoughtful overview of proposed destinations is important at this time.
   
   NASA is designing its approach to the President's Vision for Space
      Exploration (VSE) by focusing
!!! entirely on the development of a human-tended lunar outpost.
While many space science pursuits have been
      suggested for the lunar surface, it is by no means clear that many are
      uniquely or even conveniently enabled by it. With the important exception
      of science that explicitly involves geological and perhaps atmospheric
      research, much of what space scientists want to do can actually be done
      better in free space.

We'd like to share an increasingly common view within some science communities
about how major, publicly-appealing goals can be achieved by using NASA's evolving
space exploration technology and the vehicles (what is often called the "architecture")
of the President's exploration initiative.
!!! Such achievement is possible if we think more
!!      broadly about human and robotic destinations as "vantage points" on the
      Universe, including the Earth.

      Yes, we're going back to the Moon as human explorers but, as the
      architecture is developed to do that, is it going to provide capabilities
      to build, maintain, and oversee facilities in free space as well?

Might this architecture also allow us to construct the large craft that will
      eventually take people to Mars? While such free-space capabilities were
      repeatedly demonstrated with the development of the International Space
      Station (ISS) and the regular servicing of Hubble Space Telescope (HST),
      our nation has no future plans to use these capabilities in the context of
      the new architecture.
Without some serious reconsideration, a modern
      counterpart to the failure in the Apollo legacy appears to be looming:
a huge investment in capabilities that were largely shelved.
On the one
      hand, NASA plans to have us travel vast distances to Mars while, on the
      other hand, it seems willing to abandon the very in-space construction and
      maintenance capabilities that may be necessary precursors to such long
      voyages.

      It is a common theme in the evolving exploration initiative that
      destinations for our nation in space include
!!! only sites that people can walk or drive around on.
 
The Moon-to-Mars (and maybe Near Earth Objects)
      premise of the initiative would seem to explicitly define priority
      destinations as those endowed with rocks, volatiles (ices), and dust.

      Perhaps it's just backlash from the "round-and-round" frustration with ISS
      in low Earth orbit. But this definition has to be rooted in much more than
      a simple call for flags and footprints, as the architecture now being
      developed is wholly focused on getting to a place where our flags and
      footprints can already be found.
So it must be more than that.

      Our historical picture of exploration is truly well "grounded", in that
"going where no one has gone before" has
!!! almost always involved a solid surface.

From Magellan to Roald Admunsen, from Meriwether Lewis and
      William Clark to Edmund Hillary, we admire explorers through the grit they
      bring back on their boots, if not the footprints that they leave. Perhaps
      the only historical counter-examples were the early ballooning and
      aircraft pioneers, the barnstormers for whom exploration was the adventure
      of leaving the Earth's surface.

While exploration often explicitly
      involves the search for riches that would improve someone's quality of
      life—and such material riches are not as likely to be mined in the vacuum
      of free space—exploration can just as well be used to proudly assert
      endurance, planning, fortitude, and the pursuit of strategic knowledge.

      Those qualities are independent of dust and rocks. With respect to
      identifying riches,
!! exploration has a strong subtext of fence-building and property rights.
That's hard to do without a solid surface.

The Montgolfier brothers never had a chance to drive stakes into the upper
      troposphere nor did Chuck Yeager in the stratosphere nor astronauts in low
      earth orbit. Merely flying through air or space thus seems to be a lesser
      form of adventure and exploration.
That's a pity, because a picture of exploration defined by standing on rocks
!!! does not reflect the new Information Age in which we live,
where high bandwidth enabled immersion
      allows more people to come along for the adventure.

Thirty years ago, astronomical telescopes on the lunar surface
looked profoundly enabling because we simply didn't know how to
point telescopes in free space.

We do now, and we do it better—using, for example, the twenty-five-year-old
technology of the Hubble Space Telescope—than with any telescope on the surface of
            the Earth.

      While the promise of in situ resource utilization (ISRU) in a low-gravity
      potential well is an oft-cited justification for a human-based lunar
      return, its marketability and feasibility are problematical.
This promise
      has yet to excite any substantial private interest, and the engineering is
      hardly as simple as some have suggested. Moreover, using those resources
off the Moon involves in-space capabilities that NASA appears ready to abandon.

NASA's Decadal Planning Team (DPT) and the NASA Exploration Team
      (NExT), quietly constituted in the early part of the decade (see "Forging
      a vision: NASA's Decadal Planning Team and the origins of the Vision for
      Space Exploration", The Space Review, December 19, 2005), attempted
!!! to break the lock that the lunar surface had on the imagination of human
      spaceflight advocates
by identifying destinations in free space as more suitable stepping-stones to other
 scientifically-fertile destinations such as Mars.

Nevertheless, the US space agency appears once again to be focused
!!! solely on the old rocky landscape of the Moon, important as it may
      be for understanding our Solar System, but also limiting in terms of the
      vantage point it provides.

      That's not to say that free-space is being ignored.
Such free-space
      science is already substantially funded through the NASA Science Mission
      Directorate.
However, a broad commitment by the science community to the
      human exploration initiative and the architecture it develops will
 strongly depend on what else, besides the lunar surface, it can be used for.
 
From the perspective of many science investigations, the value of the
      lunar surface is limited, even without accounting for the enormous cost of
      landing and surface operations.
An exception may be studies of the Moon
      itself, for which we are seeing a renaissance of profound questions.
See,  for example, the newly released final report from the National Research
      Council's Space Studies Board "The Scientific Context for Exploration of
      the Moon".
This seminal view of the Moon as a vantage point on the history
      of the silicate planets in the Solar System is compelling, but
!!! many of the important goals may well be achieved
!!! cost-effectively using robotic
      methods with a sustainable program of robotic lunar science missions, as
      is already being accomplished very effectively on Mars.
   
  As mentioned earlier, the diminishing value of the lunar surface is due to
      advances in supporting technology.
Thirty years ago, astronomical
      telescopes on the lunar surface looked profoundly enabling because we
      simply didn't know how to point telescopes in free space. We do now, and
      we do it better—using, for example, the twenty-five-year-old technology of
      the Hubble Space Telescope (HST)—than with any telescope on the surface of
      the Earth.
A "debate" on the relative merits of the Moon for astronomy is
      found in a recent issue of Physics Today.
The situation is the same for
      the Earth sciences and observations of our Sun:
costs and operational
      simplicity seem to favor by a large margin locations in free space such as
      the Earth-Sun Lagrange points over the lunar surface.
While lunar soil may
      offer a record of solar activity that is valuable to heliophysicists,
      realtime monitoring of the Sun and the solar wind does not need to be
      anchored on regolith.
Overall, the lunar surface presents a challenging
      environment, with dust and power generation problems as well as the
      difficulty of precision soft landing.

      It is useful to point out that a focus on the value of in-space locations
      should not be misinterpreted as diminishing nor threatening the role of
      human spaceflight.
While many science communities are unexcited about the
      costs and complexity of lunar surface operations conducted by humans, many
      of the same communities have nevertheless gained substantially from human
      spaceflight.

In addition to the exciting HST servicing, astronauts were
      able to free a recalcitrant antenna on the Compton Gamma Ray Observatory
      and regenerated the Solar Max mission.

On the other hand, it is equally
      true that the human spaceflight effort promised, or at least led
      scientists to believe, that it would lead to huge science returns.
!!! That hasn't happened.

So while it is with some trepidation that we reach for
      human exploration-enabled science that has a broad scope, that shouldn't
      stop us from trying.
However, it seems wrong-headed to accept casually the
      additional costs of operating on the dusty and thermally-variable lunar
      surface where any offsetting gains seem implausible.

      Considering only the architectural elements, there are some extraordinary
      capabilities being developed by our new space exploration program.
The Orion Crew Exploration Vehicle (CEV) will be the new human transport craft
      and will, in principle, be capable of operating through cislunar space,
      perhaps even at the Sun-Earth Lagrange points, where many of our future
      science missions will be located.
Whether this would permit astronaut EVAs
      giving hands-on access to science facilities (

[RadioactiveRainbow]

Это типа очередной виток спора "человек vs робот"?

[Димитър]

Олигарху:
А Вы на русски переведите, чтобы все поняли.  :?

[Олигарх]

Олигарху:
       

                             
                               NASA Insiders Propose Stepping Stone Path to Deep
                              Space
                              By Leonard David
                              Special Correspondent, SPACE.com
                              posted: 30 July 2007
                              01:07 pm ET


                        GOLDEN, Colo. – NASA's Constellation Program – including
                        the deployment of the Orion crew vehicle replacing the
                        space shuttle – will first be assigned to International
                        Space Station flights, then propel humans and cargo to
                        the Moon. Expeditionary missions to Mars and beyond will
                        follow.

                        But there's ongoing discussion of mounting a piloted
                        mission to an asteroid – a voyage by astronauts to a
                        near-Earth object, termed NEO for short. These
                        proponents feel certain of the scientific payoff from
                        reaching, first-hand, an asteroid – perhaps even
                        becoming able to exploit these chunks of celestial
                        flotsam to further humankind's plunge into the cosmos.
                        Space technologists argue that a NEO trip could be a
                        valuable shakeout of people, equipment, and procedures
                        prior to hurling astronauts beyond the Moon to the
                        distant dunes of Mars.

                        For others, NEOs are viewed as downright dangerous, in
                        terms of a head-on collision between Earth and a space
                        rock. It's best to get to know these incoming beasts
                        ahead of time.

                        NASA's NEOphytes

                        Internal looks by a small group of NASA "NEOphytes" have
                        projected that a human trek to one of those mini-worlds
                        may involve two or three astronauts on a 90 to 120-day
                        spaceflight, including a week or two week stay at the
                        appointed asteroid.

                        Dispatching astronauts to a NEO is a sensible idea, said
                        Harrison Schmitt, Apollo 17 astronaut, geologist and
                        current chair of the NASA Advisory Council (NAC).
                        In fact, the Exploration and Space Operations
                        subcommittees of the NAC were briefed July 18 by NEO
                        study team members from the NASA Johnson Space Center,
                        although there has been no Council action on the topic.

                        Schmitt told SPACE.com: "I think examination of a NEO
                        mission and the development of the stand-by monitoring
                        systems, plans, protocols and procedures for the
                        diversion of a potentially Earth-impacting asteroid
                        would be very prudent activity for the U.S. to
                        undertake."
                        Additionally, Schmitt said that a NEO mission would be a
                        potentially important demonstration of the versatility
                        and capability of the Constellation systems and a
                        "gap-filler" before any Mars landing mission.
 
                       "So far, the arguments for asteroid science and
                        resources are interesting, but not well-developed or
                        potentially as historically or politically persuasive as
                        a demonstration of long-term Earth defense," Schmitt
                        said.

                        Extended flight

                        At this point in time, NASA has not issued any formal
                        requirements to augment the Orion spacecraft to handle a
                        piloted NEO mission, explained John Stevens, Director of
                        Business Development for the human spaceflight line of
                        work at Lockheed Martin Space Systems, near Denver,
                        Colorado.
                        However, the company – builder of the crew-carrying
                        Orion spacecraft – internally funded two years worth of
                        studies to flesh out technologies to support a diversity
                        of destinations, Stevens said.

!!! For sojourns to a near-Earth asteroid, he said, future block upgrades to
                        Orion are necessary.

                        "It's not that difficult from an architecture point of
                        view to fly by an asteroid and then come back," Stevens
                        said. But pulling off a rendezvous and docking with such
                        an object, then rocketing back to Earth, requires more
                        propulsion oomph, he noted, along with the need for
                        larger living quarters for transiting crews, as well as
                        recycling hardware to handle oxygen and water needs.
 
                       Also, any roundtrip – Earth-to-NEO-to Earth – is an
                        extended flight, way beyond that required for Moon
                        travel. So that brings up crew psychological-sociological issues.

"It's a concern...but we don't know how much of a concern," Stevens advised.
                        Stevens said that the near-Earth object human mission
                        can be viewed as an intermediate step between a Moon
                        mission and a Mars mission. "In terms of complexity and
                        the length of time that you have to stay out...it does
                        represent a good stepping stone between the kinds of
                        missions you do at the Moon and the kinds of missions
                        that you next bite off...which is the Mars mission," he
                        said.
                     
  Visualize this space

                        DigitalSpace, a privately held company based in Santa
                        Cruz, California, has just released a design simulation
                        of a notional crewed mission to an as-yet identified
                        asteroid.
                        "This visualization is DigitalSpace's design concept for
                        the mission, produced as an independent effort for the
                        benefit of an internal NASA feasibility study completed
                        in 2007," said Bruce Damer, founder of the company that
                        provides leading edge Internet content and tools for
                        communication, collaboration, and visualization.

                        The NASA study was performed to show that such a mission
                        is possible with the new Constellation architecture,
                        Damer said. DigitalSpace received input from numerous
                        experts inside and outside NASA to produce the NEO
                        mission visualization.

                        "It is important to note that this is not a NASA
                        concept, nor has NASA given it any kind of technical
                        blessing...it is a design created by the DigitalSpace
                        team to stimulate discussion in the space community,"
                        Damer emphasized.
                        Indeed, many in the space community see any pilgrimage
                        to an asteroid – by either robots or astronauts – as
                        having multiple benefits.

                        Tooling up for NEOs

                        Learning about NEOs offers much in both scientific and
                        practical terms. That's the perspective offered by Clark
                        Chapman, a planetary scientist at the Southwest Research
                        Institute's (SwRI) Department of Space Studies in
                        neighboring Boulder, Colorado.

                        The reasons are many, Chapman said: Because there are
                        many of them, because they are made of materials both
                        common and exotic compared with materials available near
                        the Earth's surface, and because they have negligible
                        gravity...they are an obvious source of raw materials
                        for future human exploration of outer space.

                        Tooling up for NEOs is already being tackled by
                        specialists at Ball Aerospace & Technologies
                        Corporation, also in Boulder. They have been looking
                        into a small, low-cost landing probe design that could
                        characterize both the surface and interior of small
                        solar system objects, such as an asteroid.

                        The device is about the size of a basketball and weighs
                        just a few pounds, said Dennis Ebbets, Senior Business
                        Development Manager for Ball Aerospace's Space Science
                        division. He and staff consultant, Richard Reinert,
                        along with Rich Dissly, Ball's Deputy Director for Solar
                        System Advanced Systems, suggest that several of the
                        probes could be hauled to a target object and deployed
                        individually.

                        Once released, these non-propulsive surface probes would
                        freefall onto an asteroid's surface and begin
                        transmitting results from their respective locales. The
                        probes are outfitted with deployable panels to ensure
                        self-righting to begin their errands.

                        Each self-energized probe might employ tiny imagers,
                        accelerometers, x-ray spectrometers, sample collection
                        and analysis gear – perhaps even utilize small explosive
                        charges to create seismic waves that help gauge an
                        asteroid's internal structure.

                        While asteroid surface probes could be deployed from an
                        automated spacecraft, they are also a "perfect
                        candidate" to be toted onboard a human expedition to a
                        near-Earth object, Ebbets told SPACE.com.

                        Ebbets said asteroids deserve attention to help figure
                        out what they are, where they come from, why they are
                        different, and why there are families of these objects
                        that are the same.

                        Additionally, "there's a non-zero chance of being hit by
                        one of these things," Ebbets noted. He said he was a big
                        fan of dropping a transponder onto an asteroid that's
                        been branded as a potential troublemaker.
                        "Putting a transponder on it would be an excellent thing
                        to do," Ebbets added. "You can get a very, very accurate
                        orbit...predict years into the future whether it's on a
                        collision course with us or not."

                        Long-delayed expectations

                        Along with the need to come to grips with scalawag
                        asteroids that could harm Earth, SwRI's Chapman senses
                        other NEO exploration outcomes.

                        "Though I am a space scientist strongly oriented toward
                        the cost-effective robotic exploration of the solar
                        system, I also grew up on science-fictional accounts of
                        human expansion into the cosmos, and I endorse that more
                        expensive - but ultimately inevitable - direction for
                        human exploration," Chapman said.

                        Chapman said that it makes sense to him that NEOs could
                        be used as "way-stations" to Mars.
"Human visits to NEOs
                        can go part-way toward understanding the challenges of
                        going to Mars, yet not invoke the most serious
                        challenges," he said.

                        Regarding concerns in some quarters that efforts to send
                        humans to NEOs may be a distraction from the main, early
                        focus of sending humans to the Moon, Chapman said:

"In the current environment where the 'Vision' dominates
                        NASA and the budget tends to restrict what we might do
                        under the umbrella of the 'Vision' to the narrowest
                        aspect of the 'Vision'...the focus must be on the Moon."
   
                    More than the Moon

                        But Chapman continued by noting that the dreams of
                        people worldwide who want to expand their long-delayed
                        expectations of going into interplanetary space, NASA –
                        assisted by the budgetary processes in the Congress –
                        must find a way to do more than just return to the Moon.

                        "I happen to believe that scientific exploration of the
                        Moon...could be extremely significant. And the Moon is
                        much more easily explored and developed than Mars, which
                        must remain a longer term challenge. But NEOs offer a
                        special, practical, and inspiring challenge that we
                        should keep on the table," Chapman explained to SPACE.com.

                        In the context of the hazard of destructive impacts by
                        NEOs on the Earth, Chapman said that "everything we can
                        learn about the physical nature of NEOs can
                        incrementally enhance our chances of dealing effectively
                        with one, should one be discovered that seriously
                        affects us."
!!!! He explained that robotic exploration of such a NEO would be essentially
!!!  as good as human exploration of that threatening object.

                        "But the generic exploration of NEOs – even if solely in
                        the goal of getting to Mars - can have side benefits not
                        only for understanding the range of issues we might have
                        in dealing with a threatening NEO, but also in learning
                        how we might mine the resources of NEOs for future use
                        in human exploration of the solar system," Chapman
                        concluded.

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How to land a spacecraft on an asteroid
Digital simulations show how NASA might land spacecraft, people on an asteroid,
possibly paving the way for trips to deep space.

Images: Vision for an asteroid mission
By Stefanie Olsen
Staff Writer, CNET News.com

Published: July 30, 2007, 4:00 AM PDT
TalkBackE-mailPrint del.icio.us Digg this
 
NASA is exploring the possibility of sending astronauts to an asteroid, with
hopes of making deep-space exploration more feasible.
The DigitalSpace Commons, a Santa Cruz, Calif.-based company that develops an
open-source 3D rendering system, has come up with the design for a new NASA
spacecraft and a mission that could eventually allow humans to land on and
explore an asteroid, or so-called near-Earth objects (NEO). The privately held
company plans to unveil the design publicly Monday.

The project dovetails with NASA's Constellation Program, a plan to send
astronauts back to the moon by 2020. Along with the lunar mission, the space
agency is investigating the possibility of using its future crew navigation
vehicle for missions to an asteroid, which could help scientists better
understand the minor planets or assist in eventually getting humans to Mars.
 
Over the last six months, NASA studied how it might modify its own lunar vehicle
for trips to NEOs and found that it was feasible, according to David Morrison, a
senior scientist in NASA's Astrobiology Institute.
"The concept of human flights to near-Earth objects is exciting for science, and
it's a logical, technological stepping stone to Mars because it's intermediate
in flight length," said Morrison. "It's not literally on the way, but it's on
the way for developing the technology for deep space."
 
Last summer, DigitalSpace said NASA asked it to develop a simulation for such a
mission that would draw on the Constellation Program's spacecraft architecture.
DigitalSpace's simulations attempt to deal with the unique nature of landing on
an NEO.

For starters, gravity is almost nonexistent on an asteroid, which can be as
small as only a few hundred feet across or as big as tens of miles in diameter.

And because asteroids have rocky, sometimes crumbly surfaces, DigitalSpace's
proposed spacecraft includes a system that would anchor it like a boat in a
harbor.
The design includes a ring of airbags with sensors to detect the
stability of the ground. Once a landing is deemed secure, barbed tethers would
deploy to latch the craft onto the surface of the NEO. Like car airbags, the
ship's airbags would compress against an asteroid's surface.

"On an asteroid, it's a different environment that requires a whole new way to
land a spacecraft," said Bruce Damer, president and CEO of DigitalSpace. "It's
like insects being blown around by the wind; they have all this technology to
hold onto your arm."

A large part of the interest in asteroids is self-preservation, given that they
have hit Earth in centuries past, causing mass destruction. In 1908, for
example, a meteor struck the deep woods in Siberia, unleashing the energy
equivalent of a 10- to 15-megaton atomic bomb. As a result, scientists want to
study the composition and behavior of asteroids and better predict their
trajectories. Morrison said scientists have only discovered a small fraction of
the millions of asteroids that could be potential hits.
In addition, asteroids are composed of materials that could be useful for
replenishing supplies on lengthy missions into space far in the future.
"In the long term, we don't know enough about asteroids and how much it would
take to use them for resources," said Morrison.

 He said the problem with traveling to an asteroid is finding one with an orbit
that's similar to Earth's, so that astronauts could get there and back in a
short period of time, less than roughly three months.
NASA needs to conduct
surveys to find a suitable asteroid for travel, he said, but DigitalSpace
projects that such a flight with NEO targets could be feasible by 2017.

NASA's feasibility study looked at altering its lunar crew-exploration vehicle
for an NEO mission in such a way that it would hold fewer astronauts (to make
room for sufficient supplies) and include a different configuration of launch
rockets, according to Morrison.

DigitalSpace then came up with a detailed configuration that could deal with the
unique conditions of an asteroid, giving a better picture of how it might be
done.
"We wanted to show the world how you might do a human mission to an asteroid,"
said Damer.
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[Олигарх]

A giant leap: Robots or astronauts? - CNN.com

 By Michelle Jana Chan
     
LONDON, England (CNN) -- Can everyone be an astronomer? It certainly seems that
way, especially with some of the latest tools at our fingertips, like Google
Sky, which allows Internet users to navigate through a digitized map of space.
But some say virtual astronomy is not just for amateurs and should also be the
way forward for professional space exploration.
A future of virtual astronauts, too.

The future? The James Webb Space Telescope is the successor of Hubble.
 Bob Park, professor of physics at the University of Maryland, believes that

!!! virtual space exploration using telerobots (which humans control from the
ground) is a better solution than sending astronauts,
which he calls a waste of resources.
"We've gone about as far as we can with manned space missions," Park
says. "We could go to Mars at enormous expense but what would a human do when he
got there? We can't do much locked in a space suit. There isn't much to hear
except a very low rumble from the Martian wind.
!!! The only sense that would be available to us is our eyes
and we can build robots with much better eyes than humans.

Already, the little rovers on Mars right now can focus in on a distant
mountain or a grain of sand. We can build telescopes on our robots with any sort
of visual capability that we want."

To take man to Mars? Or to take us to Mars via a robot (which we are doing
already)?
Park says there is
!!! little dissent in the scientific community about which is better for science,
although he concedes there is an element of romance lost by using robots.

"Sense of adventure is the only thing going for manned space travel," Park says.
"But it's time to have a grown-up attitude to adventure.
If you want adventure, go bungee jumping."

Director of the United Kingdom Astronomy Technology Centre in Edinburgh, Scotland,
Ian Robson agrees that the science points us away from manned space travel.

"You can always achieve more by robotic missions," Robson says.
"If I had the budget, I would spend it on robotic missions.
!!! But if I was a politician I would have to think again."

Certainly, the manned space mission has been what's captured the public's
imagination in the past.
"The cultural experience of watching the Apollo landing was so dramatic," Robson says,
 "but if we all switched on our television sets
today to see the first person land on Mars and career around,
!!! maybe it wouldn't have such an impact."

That could be because there are so many more ways of experiencing space
exploration today, like the recently launched Google Sky, described as a
'virtual telescope'.
It is the latest feature from the mapping service Google
Earth but instead of focusing in on our planet, Google Sky allows Internet users
to turn their zoom around and explore space, with the ability to navigate around
over 100 million individual stars and 200 million galaxies. "We thought we could
use the same base technology (as Google Earth) but put it in reverse and look
outwards," says Ed Parsons, Google's Geospatial Technologist.
...
...

Предполагаемый полет Ориона к одному из астероидов класса NEO можно рассматривать
как сокращенную версию проекта 1966 г.!
Хотя нет, в отличие от этого древнего проекта Орион должен "приземляться" на астероид
и астронавт попрыгает по нему!
Это плюс , так как зрелише астрнавта на тверди Луны/Марса/астероида оказывает
чарующее воздействие на публику (см. выше  The Space Review: Destinations for exploration:
more than just rocks? http://www.thespacereview.com/article/912/1
Human space exploration has traditionally been inspired by ultimate
destinations beyond the Earth and designed to reach them efficiently and safely.
!!! Specifically, these destinations have been bodies in our solar system. ),

что важно для тех, кто будет принимать решение:
 
"You can always achieve more by robotic missions," Robson says.
"If I had the budget, I would spend it on robotic missions.
!!! But if I was a politician I would have to think !!! again."

Но наверняка, КА типа NEAR + КА для взятия образца и доставки его на Землю
скорее всего решат, если не все, то основные научные залачи полета Ориона к астероиду,
Причем намного дешевле.  
Тем более, что заговорили о автомате-предшественнике для Ориона (см. выше
 NASA manned NEO mission needs robot test-15/06/2007-London-Flightglobal.comFlightGlobal
http://www.spacetoday.net/getarticle.php3?id=102297), который,очевидно,
в той или иной степени будет КА типа NEAR.
Тогда что остается Ориону? Взятие образцов и его доставка ...

Altair VI: Manned Eros flyby
http://altairvi.blogspot.com/2007/06/manned-flyby-mission-to-eros.html
David S. F. Portree's blog
Wednesday, June 13, 2007
Manned Eros flyby
 
German astronomer Gustav Witt discovered the asteroid Eros on August 13, 1898.
Eros was both the first asteroid found to orbit entirely outside of the Asteroid
Belt and the first known planet-crosser; its path crosses that of Mars. In March
1966, Eugene Smith, an engineer at Northrop Space Laboratories in Hawthorne,
California, presented a paper on a piloted Eros flyby mission at the Third Space
Congress in Cocoa, Florida. In it, he wrote that Eros exploration might help
scientists understand Main Belt asteroids and small planetary moons (for
example, the martian satellites Deimos and Phobos). He noted that Eros would
pass within 14 million miles of Earth in January 1975.
...
...
Smith's 527-day Eros flyby mission would begin with launch and Earth departure
on May 3, 1974, at the opening of a 30-day launch window.
...
On January 18, 1975, the astronauts would begin tracking Eros using radar, a
five-foot-long reflecting telescope with a 30-inch primary mirror, and other
instruments mounted in the EMM's sensor turret.
On January 23, 1975, they would
fire the ESM engines to ensure an Eros close-approach distance of about 50 miles
and begin gathering Eros science data. About eight hours before closest
approach, the astronauts would catapult a 200-pound automated probe toward the
asteroid. The EMM's dish antenna would relay to Earth data from the probe's TV
camera and other instruments.

Closest approach to Eros would occur about 14 million miles from Earth on
January 28. The piloted spacecraft would spend about 90 seconds within 200 miles
of asteroid's sunlit side and about 30 seconds within 100 miles.
On January 30,
1975, the crew would end Eros tracking and fire the ESM engines to correct
course deviations imparted by the January 23 maneuver, the automated probe
launch, and the weak tug of Eros' gravity.

The astronauts would load the ECM with scientific data and check out its systems
on October 10, 1975. On October 12, they would abandon the EMM and use the ESM
engines to place the ECM on course for Earth atmosphere reentry. They would then
jettison the ESM, reenter Earth's atmosphere at about 40,000 feet per second,
and descend to the surface on parachutes.

Congress killed NASA's plans for piloted flyby missions in August 1967. The only
U.S. piloted mission of 1975 was the Apollo-Soyuz Test Project, which saw the
final Apollo spacecraft dock with the Soviet Soyuz 19 spacecraft in low-Earth
orbit.

!!!
When NASA at last explored a near-Earth asteroid, it explored Eros.
The $112-million Near-Earth Asteroid Rendezvous (NEAR) mission - the first mission
in NASA's new low-cost Discovery Program - left Earth on February 17, 1996, more
than 20 years after the planned launch date of Smith's piloted Eros flyby.

On December 20, 1998, NEAR failed to enter Eros orbit because its computer
aborted a crucial engine burn. Three days later, after some quick reprogramming,
NEAR flew past the 22-mile-long, 13-mile-wide asteroid at a distance of 2375
miles, returning 222 images.

On February 14, 2000, after an additional revolution about the Sun, NEAR at last
orbited its target. NASA renamed the spacecraft NEAR Shoemaker in March 2000 to
commemorate renowned planetary geologist and comet discoverer Eugene Shoemaker,
who had died in a car crash in Australia in 1997. In the year that followed, the
spacecraft radioed to Earth more than 160,000 close-up images of Eros.

Though designed as an orbiter, NEAR Shoemaker succeeded in landing on Eros on
February 12, 2001. It returned gamma-ray spectrometry data from the asteroid's
surface until February 28, 2001.

В статье не приводится сравнений научных программ пилотируемого пролета Эроса и зонда NEAR.
Скорей всего, они были примерно равнозначны.