TacSat-4 - Minotaur IV - Kodiak LP-1 - 27.09.2011 15:49 UTC

[Старый]

4 часа на 6 = 24 часа.
6 пролетов в сутки

Чтото у меня нацело не делится. Или там надо учитывать прецессию плоскости?

[ivan555]

4 часа на 6 = 24 часа.
6 пролетов в сутки

Чтото у меня нацело не делится. Или там надо учитывать прецессию плоскости?

Ну я в такие тонкости не вдавался. Может там не точно 4 часа, не знаю. Для простаков на каком-то американском сайте так объясняли.

[Космос-3794]

Sierra Nevada Corporation's (SNC) разработала и изготовила бортовую авионику для TacSat-4. Аналогичный бортовой процессор также будет использоваться на коммерческих ORBCOMM Generation 2:

Sierra Nevada Corporation's (SNC) Space Systems has revealed its role in the recently-launched TacSat-4 mission. The Universal Interface Electronics (UIE) unit developed by SNC and launched as part of the TacSat-4 mission on September 27th. The UIE unit is a prototype of SNC's distributed, modular avionics architecture developed as part of the DoD plug and play responsive satellite initiative. The primary purpose of the UIE device is to enable rapid interfacing of various devices with differing interface protocols via firmware reprogramming with the intent of eliminating expensive and time consuming hardware modifications and requalification. TacSat-4, sponsored by the Office of Naval Research, is the latest in a series of satellites intended to demonstrate an ability to rapidly deploy small, low-cost spacecraft that can meet the needs of military commanders at the theater level. It is part of a larger DoD initiative known as Operationally Responsive Space (ORS). SNC's Space Systems group provided the satellite for the Air Force Research Laboratory's (AFRL) TacSat-2 ISR satellite, which launched in December of 2006, and the SPA Avionics Experiment (SAE) payload on TACSat-3 that launched in May of 2009. With regards to the significance of the TacSat-4 experiment, Jeff Summers, SNC's Space System's VP of Technology, said, "The development and subsequent flight of the UIE on the TacSat-4 mission is important to SNC as it represents validation of the on-board processor base lined in all 18 of SNC's commercial ORBCOMM Generation 2 satellites."

http://www.satnews.com/cgi-bin/story.cgi?number=627016945

[G.K.]

Цирк...
...
 А сейчас пустили вполне себе нормальный военный (хоть и экспериментальный) спутник связи - и элементы выдаются открыто...

Продолжение: они даже ЭПР выдали  
 0,6719

[Sharicoff]

0,6719

Маловато. Похоже, антенну еще не раскрыл.

[Salo]

http://www.spaceflightnow.com/minotaur/tacsat4/111008update/

Low-cost UHF antenna deployed on Navy satellite[/size]
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: October 8, 2011

The umbrella-like antenna on the U.S. Navy's experimental TacSat 4 communications satellite has popped open and begun relaying voice messages a week after launching from southern Alaska, according to mission officials.


Photo of the TacSat 4 UHF communications antenna during ground testing. Credit: Naval Research Laboratory
 
The 12-foot-diameter antenna opened three days after the craft's Sept. 27 launch aboard a Minotaur 4 rocket from Kodiak Launch Complex in Alaska.

TacSat 4 was developed by the Naval Research Laboratory, marking that organizations 100th satellite since the dawn of the space age. Its objective is to demonstrate advanced communications capabilities for U.S. forces deployed in war zones like Afghanistan.

Mike Hurley, the lab's head of spacecraft development, said the TacSat 4 "antenna has deployed and is working well," adding the satellite has already started processing voice data to and from user radios on the ground.

Designed and built in-house by the Navy Research Laboratory for approximately $2 million, the 60-pound antenna was folded up like an umbrella for launch. A strap connected with a breakable joint held the antenna in the launch position until the command was issued to deploy, then 20 springs pushed out the antenna in a few seconds.

Commercial satellite antenna-builders have approached the Navy for details on the TacSat 4 design, according to Hurley. Many satellite antennas are much more costly, and industrial proposals to build TacSat 4's antenna were too expensive for the mission's limited budget.

TacSat 4's payload includes 10 UHF communications channels. According to military officials, UHF communications make up for a lack of bandwidth with high reliability.

From its unique orbit between 465 miles and 7,457 miles above Earth, TacSat 4's communications signals can reach existing handheld radios with deployed military units.

Legacy military communications satellites are stationed three times further from Earth, meaning its signals aren't as strong and troops need a larger radio to transmit and receive messages.

Although TacSat 4 can only cover part of the Earth at one time, a fleet of four or five similar satellites could provide global coverage and facilitate "communications on the move" for U.S. forces. Military personnel now must stop and point a large antenna toward a satellite to receive communications.

"TacSat-4 supports a critical warfighting requirement: communication," said Rear Adm. Nevin Carr, the chief of naval research. "We've developed a technology that will supplement traditional satellites, giving military personnel on the ground another outlet for data transmission and facilitating 'comms on the move.'"

Hurley said testing of the TacSat 4 spacecraft should be complete next week, and there's another four-to-five weeks of testing of ground terminals and user equipment before the real mission begins.

The $118 million TacSat 4 mission is designed for a one-year test campaign to show the utility of the added UHF communications capacity, then the satellite could be transitioned to normal military operations.

TacSat 4 is part of the Defense Department's Operationally Responsive Space office, which was established to develop niche satellites with less funding than traditional military programs.[/size]

Видео пуска:

[G.K.]

0,6719

Маловато. Похоже, антенну еще не раскрыл.

Так лучше ? 3,1623     

[Брабонт]

По одному измерению мало, но ход мысли правильный.

[G.K.]

По одному измерению мало, но ход мысли правильный.

Их пока всего два    Буду информировать общественность по мере развития событий

Ну и согласен с Шариковым на 100% - кучу мелюзги они засекретили, а этого нет. Гласность настала что-ли временная...  :roll:

[Sharicoff]

кучу мелюзги они засекретили, а этого нет. Гласность настала что-ли временная...  :roll:

Нет, с этим-то как раз все стандартно - на Таксаты и раньше все выдавалось, не смотря на их военно-экспериментальность. Тут случай с прошлогодним кодьякским пуском явно выбивается, вот что непонятно.

[Старый]

Объясните мне кто-нибудь про сабж - почему такая орбита?

[Брабонт]

239 мин х 6 = 1434 мин. Без двух минут звёздные сутки - кратность налицо.

[Старый]

239 мин х 6 = 1434 мин. Без двух минут звёздные сутки - кратность налицо.

Зачем шестиразовая кратность то? Почему не орбита типа Молния?
 Впрочем, если наземные антены не направленые то зачем вообще кратность?

[Брабонт]

Видимо, оптимизация по уровню сигнала / доплеру?

[Старый]

Кстати, а когда у него орбита стала 239 минут?

[Брабонт]

the Operationally Responsive Space Office and the Defense satellite acquisition community will evaluate the performance and user feedback from TacSat-4 to determine if follow-on birds will be procured.

Т.е. с прицелом на сеть КА.

[Брабонт]

Кстати, а когда у него орбита стала 239 минут?

[Старый]

Спасибо.

[G.K.]

Вышло новое ЭПР:  1,1630
То ли он съежился , то ли боком к радару повернулся.

[Liss]

А что, коллеги, все-таки нотифицированная негеостационарная заявка USTRO-1 прокатит для 10 UHF-каналов на 25 кГц каждый на нашей птичке?
К сожалению, слышали от него пока только S-диапазон :-(