TESS — Transiting Exoplanet Survey Satellite (Спутник наблюдения за транзитами экзопланет)- 19.04.18

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 1 ч. назад

The @NASA_TESS first apogee maneuver (A1M) was successfully completed yesterday. This burn was a 50 second checkout burn to characterize the performance of the #TESS thrusters.

Jonathan McDowell‏Подлинная учетная запись @planet4589 1 мин. назад

I think by "yesterday" @NASA_TESS mean to say 0145 UTC this morning (which was yesterday in US EDT). At least, that was the originally scheduled time

2 мин. назад

Oops I confused the engine burn time with the time of apogee. TESS first apogee was at 0235 UTC Apr 22, not 0145 UTC. Apogee height was 272166 km

[tnt22]

Jonathan McDowell‏Подлинная учетная запись @planet4589 13 мин. назад

TESS reached first apogee at 0145 UTC this morning and is now falling back towards Earth (don't worry, it will miss). Perigee at 0542 UTC Apr 25 at 2232 km altitude, SW of Baja

Jonathan McDowell‏Подлинная учетная запись @planet4589 2 мин. назад

Oops I confused the engine burn time with the time of apogee. TESS first apogee was at 0235 UTC Apr 22, not 0145 UTC. Apogee height was 272166 km

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 2 ч. назад

The first stage booster from @NASA_TESS's @SpaceX launch, B1045, is back in port aboard the drone ship Of Course I Still Love You. This is the 24th successful Falcon booster recovery from SpaceX.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 2 ч. назад

The @NASA_TESS systems engineer described the @NASA_TDRS "initial acquisition of #TESS was a thing of beauty." After TDRS acquired TESS, handover to Deep Space Network was completed for the duration of TESS operations. Thanks @NASASCaN for the support!

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 32 мин. назад

.@NASA_TESS current speed (at about 22 Apr 2018 15:46 UTC / 11:46 AM EST) was approximately 0.373 km/s. It will be increasing until #TESS reaches perigee at about 25 Apr 2018 05:42 UTC / 1:42 PM at which point it will be approximately 9.51 km/s.

[hlynin]

Выложил сегодня:
— Джордж Р. Рикер и др. «Спутник для съемки транзита экзопланет» (George R. Ricker et al., Transiting Exoplanet Survey Satellite) (на англ.) «Journal of Astronomical Telescopes Instruments and Systems», том 1, №1, 2015 г., 10 pp. в pdf - 2,24 Мб
— НАСА. Обзор миссии TESS (The TESS Science Writer's Guide) (на англ.) NASA. April 2018 в pdf - 4,41 Мб

[tnt22]

https://spaceflightnow.com/2018/04/23/after-terrific-launch-tess-nears-first-major-orbit-raising-burn/

After "terrific" launch, TESS nears first major orbit-raising burn
April 23, 2018 Stephen Clark


Artist's concept of NASA's Transiting Exoplanet Survey Satellite in orbit. Credit: Orbital ATK

NASA's new planet-hunting TESS observatory completed its first post-launch thruster firing Saturday, setting up for a big boost Wednesday that will send the spacecraft toward the moon for a flyby next month, the next maneuvers in a two-month process to reach the mission's final science orbit in mid-June.

The Transiting Exoplanet Survey Satellite fired its thrusters Saturday as it reached apogee, the most distant point in its looping elliptical orbit around Earth, nearly 170,000 miles (around 272,000 kilometers) in altitude.

Спойлер

The rocket burn was planned as a checkout of TESS's hydrazine-fueled propulsion system, and only nudged the satellite's perigee, or orbital low point, slightly higher than the spacecraft's initial perigee less than 200 miles (about 300 kilometers) above Earth.

TESS launched Wednesday atop a SpaceX Falcon 9 rocket fr om Cape Canaveral. The Falcon 9's upper stage accomplished two engine firings before deploying the 798-pound (362-kilogram) observatory around 50 minutes after liftoff.

The launch placed TESS into a preliminary oval-shaped transfer orbit. The satellite will carefully maneuver into its operational perch over the next two months, with the first major step planned for early Wednesday, when TESS swings back near Earth at its first perigee since launch, according to Robert Lockwood, TESS program manager at Orbital ATK, which built and operates the spacecraft for NASA.

Five thrusters mounted at the base of the TESS spacecraft are used for major orbital adjustments, while four spinning reaction wheels inside the satellite keep it properly pointed.

The first of three planned "perigee burns" Wednesday will do most of the lifting to place TESS on a trajectory to encounter the moon May 17, passing by at a distance of roughly 5,000 miles (8,000 kilometers) and using lunar gravity to drastically reshape its orbit around Earth.

Lockwood said in an interview Thursday that the two additional perigee burns planned at the end of TESS's second and third orbits for fine-tuning, or if the first maneuver is not accomplished as planned.

Since TESS's launch last week, ground controllers at Orbital ATK's headquarters in Dulles, Virginia, have completed communications system tests, computer checkouts and other procedures to ensure the spacecraft is healthy.


TESS separates from the upper stage of its Falcon 9 rocket around 50 minutes after liftoff while flying over the Indian Ocean. Credit: SpaceX

In concert with preparations for the mission's first major engine burn, engineers in Dulles aim to switch on the data processing unit for TESS's four imaging cameras late Wednesday, followed by activation of the cameras themselves a few hours later, Lockwood said.

TESS carries four 16.8-megapixel cameras, each fitted with four red-sensitive CCD detectors, designed to detect planets transiting in front of their host stars. The cameras will search for brief dips in starlight to find the planets, and sophisticated software algorithms will allow astronomers to scan wide swaths of the sky once full-frame images are downlinked to Earth.

During TESS's two-year, $337 million mission, the MIT-built cameras will survey more than 85 percent of the sky, looking at approximately 200,000 pre-selected bright, nearby stars, including the 6,000 or so stars that are visible to the naked eye in the night sky.

TESS will primarily look at M-dwarf stars, which are smaller and cooler than the sun, and make up the majority of the stars in the Milky Way galaxy. Also called red dwarfs, the stars that are TESS's focus have not been thoroughly investigated to determine whether they harbor their own solar systems.

George Ricker, who leads the TESS science team at MIT's Kavli Institute for Astrophysics and Space Research, said the exoplanet surveyor is a "finder scope" for the planned James Webb Space Telescope and huge ground-based observatories.

"TESS is a survey machine, and it's going to find the very best planets for us to follow-up, and among that category are these small rocky planets, transiting small red dwarf stars," said Sara Seager, deputy science director on the TESS mission at MIT.

Ricker said he expects TESS to find between 500 and 1,000 planets that are between one and three times the size of Earth. Up to 20,000 planets the size of Neptune or Jupiter could be discovered by TESS, he said.

TESS will build on discoveries made by NASA's Kepler observatory, which astronomers have used to find more than 2,600 exoplanets. But the worlds found by Kepler are much farther away than the ones that TESS will try to detect, and Kepler only looked at certain blocks of the sky.

The switch-on of TESS's cameras this week will kick off steps to begin taking test images to ensure the instrument works as designed.


An illustration of the phasing orbits to be employed by TESS on the way to its final science orbit, labeled P/2 in this image. Credit: NASA

The lunar flyby next month will loop TESS into an orbit that takes it well beyond the moon, and a final major thruster firing will reduce the satellite's apogee altitude in June.

By June 17, TESS will be in its final science orbit and ready to begin the planet hunt, Lockwood said.

TESS will end up in an orbit resonant with the moon's, ranging between 67,000 miles (108,000 kilometers) and 233,000 miles (376,000 kilometers) from Earth. In that orbit, TESS will make one lap around Earth every 13.7 days, about half the time it takes the moon to circle the Earth.

The moon's gravity will tug on TESS at a 90-degree angle each time the satellite passes through the moon's orbit, pulling on the spacecraft from one direction as TESS climbs away from Earth, then the opposite direction as it descends back toward the planet.

Thanks to the moon, TESS's "just right" orbit is gravitationally stable, requiring no maintenance burns to keep spacecraft in the correct location for scientific observations. TESS has enough fuel to keep up its exoplanet hunt for as long as 20 or 30 years, assuming NASA funding and spacecraft components remain robust, Ricker said.

"The overall effect is it actually stabilizes the orbit for TESS," Ricker said before the launch. "This is a type of orbit that's normally unstable. If you aren't careful about the way that you launch into this orbit, you're almost guaranteed to hit the moon within four years. There's a delicate balance that's involved in staying in this orbit, and there's a lot of effort that's gone into it.

"But if you actually manage to do this, this orbit is actually stable for decades. There's no station-keeping required. You don't have to have thrusters or anything ... to maintain the orbit. So it's a very elegant solution to this problem."

The mission's unique orbit also has other advantages. It stays well above Earth's radiation belts, which pose hazards to spacecraft electronics and imaging sensors, but it comes close enough to Earth to beam imagery back to scientists through NASA's Deep Space Network at high rates.

After more than 300 hours of continuous, uninterrupted science observations, TESS will turn and point its Ka-band high-gain antenna toward Earth at perigee, radioing full-frame images to the ground at up to 109 megabits per second, a blistering pace compared to most NASA science missions.

TESS will spend the first year of its mission surveying the southern sky, then will switch to the northern sky in 2019.

For Lockwood, who has worked on the TESS mission for eight years, last week's launch was a turning point.


Robert Lockwood (at right), Orbital ATK's TESS program manager, speaks with members of NASA's social media group before launch last week. Credit: NASA/Ben Smegelsky

"For a while, it didn't really feel real," Lockwood said. "I'd been there so close to the hardware for so long, and then all of a sudden it's not here.

"There was that brief period wh ere I had a surreal feeling, it's no longer around. It's like a kid leaving to go to college, and I've had four kids leave to go to college."

The launch was "terrific," Lockwood said, timed perfectly and putting TESS on the right trajectory to begin the mission's orbital dance with the moon.

TESS started a pre-programmed sequence after separating from the upper stage of SpaceX's Falcon 9 rocket, and controllers received telemetry moments after the satellite's deployment over the Indian Ocean. The satellite's two power-generating solar array wings unfurled to start generating electricity.

"A lot of guys ran outside to go watch the rocket, but I stayed inside watching (data) on the console," Lockwood said. "For me, it's when it comes off the top of the rocket, and I'm waiting for telemetry to come, and I'm waiting for the solar arrays to deploy. That's when I'm sighing a big sigh of relief."

[свернуть]

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 9 мин. назад

This plot shows the reorientation to the burn attitude. Because the #TESS S/C is rotating the Doppler will change slightly. The burn was at 4/22:01:59 (UTC) with a reorientation after the burn. The plot matches this scenario.

Scott Tilley‏ @coastal8049 21 ч. назад

#TESS continues it ascent toward first apogee. This data obtained yesterday shows no pronounced periodic behaviours in signal frequency or amplitude, previous days show similar characteristics. Sometimes the beacon shifts frequency a little or switches off...

Спойлер

[свернуть]

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 1 ч. назад

Yesterday @NASA_TESS performed star tracker to gyro / Reaction Wheel Assemblies (RWA) calibration. Observatory is performing great with no issues. #TESS

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 29 мин. назад

.@NASA_TESS remains in Coarse Pointing Inertial, all subsystems are nominal. #TESS continues to make contact with the Deep Space Network. The on-board orbit propagator was initialized and is now running. Additional observatory subsystems are planned for check out today.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 3 ч. назад

.@NASA_TESS successfully completed the first perigee maneuver (PM1). Initial indications are that the burn was nominal. P1M is the second of six on orbit burns for #TESS to reach its final science orbit.

[tnt22]

НОРАД опубликовал набор TLE на TESS

Код Выделить Развернуть

0 TESS
1 43435U 18038A   18115.29086810 -.00003846  00000-0  00000+0 0  9990
2 43435  28.3750  35.2670 9533314 231.1720   2.1580  0.10952829    16

[tnt22]

https://spaceflightnow.com/2018/04/25/nasas-new-planet-hunting-satellite-begins-climb-into-science-orbit/

NASA's new planet-hunting satellite begins climb into science orbit
April 25, 2018 Stephen Clark

Looping back near Earth for the first time since its launch one week ago, NASA's Transiting Exoplanet Survey Satellite fired its thrusters early Wednesday to begin boosting its orbit toward the moon for a May 17 gravity assist maneuver that will help catapult the probe into its unique science orbit.

The spacecraft's thrusters ignited early Thursday to raise the farthest point of TESS's orbit around Earth closer to the moon. The maneuver was timed as TESS reached its first perigee — the low point of its elongated orbit — since launching April 18 from Cape Canaveral aboard a SpaceX Falcon 9 rocket.

The Falcon 9 launcher deposited TESS into an elliptical orbit stretching around 170,000 miles (270,000 kilometers) from Earth. TESS briefly fired its thrusters Saturday as it reached the farthest point, or apogee, of its initial orbit to raise its perigee from around 150 miles (250 kilometers) to around 1,400 miles (2,250 kilometers).

The next maneuver accomplished early Wednesday positioned TESS's apogee at approximately 220,000 miles (354,000 kilometers), more than 90 percent of the distance of the moon's orbit, according to tracking data published by the U.S. military.

Спойлер

Artist's illustration of TESS in space. Credit: NASA/Goddard

Wednesday's thruster firing was the second of six maneuvers planned to send TESS into its final operational orbit. Another burn next week will be timed to occur as TESS reaches its new apogee, followed by two additional perigee maneuvers that will fine-tune the satellite's trajectory and set up for a flyby of the moon May 17.

The lunar flyby next month — targeting a distance of around 5,000 miles (8,000 kilometers) from the moon — will loop TESS into an orbit that takes it well beyond lunar distance, and a final major thruster firing will reduce the satellite's apogee altitude in June.

By June 17, TESS will be in its final science orbit and ready to begin the planet hunt.

TESS will end up in an orbit resonant with the moon's, ranging between 67,000 miles (108,000 kilometers) and 233,000 miles (376,000 kilometers) from Earth. In that orbit, TESS will make one lap around Earth every 13.7 days, about half the time it takes the moon to circle the Earth.


Artist's illustration of the TESS mission's three orbit phasing loops before the lunar flyby next month. The moon's orbit is marked by the dashed path at right. Credit: NASA

Since the launch April 18, ground controllers at Orbital ATK in Dulles, Virginia, which built the spacecraft, have switched on key components on the satellite, including reaction wheels and star trackers used to keep TESS properly pointed in space. On Wednesday, engineers sent commands to turn on the satellite's Ka-band transmitter, which routes signals through a high-gain antenna needed to beam full-frame images back to Earth from TESS's four 16.8-megapixel science cameras.

Controllers planned to begin activating the cameras as soon as Thursday, beginning several weeks of calibrations and checkouts to make sure the MIT-built imagers are ready science observations.

Each of the four cameras are fitted with four red-sensitive CCD detectors, designed to detect planets transiting in front of their host stars. The cameras will search for brief dips in starlight to find the planets, and sophisticated software algorithms will allow astronomers to scan wide swaths of the sky once full-frame images are downlinked to Earth.

During TESS's two-year, $337 million mission, the MIT-built cameras will survey more than 85 percent of the sky, looking at approximately 200,000 pre-selected bright, nearby stars, including the 6,000 or so stars that are visible to the naked eye in the night sky.

Read our earlier story for details on the mission.

[свернуть]

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 17 ч. назад

.@NASA_TESS Mission Update: The Ka-band transmitter and Traveling Wave Tube Amplifier were turned on. @NASASCaN's Deep Space Network successfully locked on to the Ka signal immediately. The link showed a strong link margin with no errors.

16 ч. назад

.@NASA_TESS Mission Update: The #TESS ADHU (data handling unit computer for the instrument from @SEAKR_Eng) was turned on. Checkout confirmed all nominal. #TESS sent data from the ADHU to the Ka Transmitter and received packets at DSN without errors.

[tnt22]

Jonathan McDowell‏Подлинная учетная запись @planet4589 5 ч. назад

TESS is approaching its second apogee - at 1903 UTC today it will be 353440 km above the Earth's surface and start on the downward arc of its second orbit.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 15 ч. назад

.@NASA_TESS Mission Update: Team decided that the second apogee maneuver (Apogee 2 maneuver (A2M)), was not necessary based on the good system performance during the first two maneuvers. Spacecraft subsystems continue to operate nominally.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 3 ч. назад

.@NASA_TESS Mission Update: The four cameras for #TESS are now powered on and will begin collecting data for the calibration process which will last until mid June.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 5 ч назад

.@NASA_TESS Mission Update: The #TESS team were successful in putting TESS in Fine Pointing Mode (instrument supplying quaternions) for the first time as part of instrument commissioning.

[tnt22]

NASA_TESS‏Подлинная учетная запись @NASA_TESS 4 мин. назад

.@NASA_TESS Mission Update: #TESS continued fine pointing data collection for instrument calibration. The #TESS cameras are being slowly cooled to their operating temperature of -80°C.

[tnt22]

Jonathan McDowell‏Подлинная учетная запись @planet4589 10 мин. назад

After yesterday's perigee 2, TESS is back out 200,000 km from Earth heading towards another apogee, which it will reach on May 8 2214 UTC