Talk:Compton Gamma Ray Observatory

BATSE

Deserves its own page, rather than a redirection to CGRO. Rod57 (talk) 17:39, 21 November 2007 (UTC)

The BATSE experiment on the Compton Gamma Ray Observatory: Status and some early results has diagrams and NASA refs. - Rod57 (talk) 02:38, 18 March 2013 (UTC)

How accurately could BATSE localise bursts ?

"BATSE Operations and Data Analysis " Pendleton 1995 says the locburst algorithm improved locations from 4 degrees RMS error to 1-2 degrees. - Rod57 (talk) 02:30, 18 March 2013 (UTC)

How were bursts/events analysed and followed up ?

BATSE has detail - Rod57 (talk) 03:30, 18 March 2013 (UTC)

Info to find sources for

• CGRO was designed for in-orbit refuelling/servicing.
• After an on-board gamma ray detection by BATSE an OSSE detector could automatically slew to observe the calculated source region. Source direction determined in ? sec by comparing count rates between the 8 BATSE sensors.
• fuel line/valve problems, detected soon after release from the shuttle, discouraged frequent minor orbital reboosts.
• The early deorbit prevented meeting a mission objective of observing a major solar flare.
• Each BATSE module had 3 photomultipler tubes as detectors.

Google finds sources for all the above. - Rod57 (talk) 00:37, 19 March 2013 (UTC)

Well, its resting in pieces now but hopefully more information can be added to the article. Fotaun (talk) 21:00, 17 November 2016 (UTC)

Smithsonian had wanted it recovered in shuttle for them to display! - Rod57 (talk) 15:24, 2 April 2021 (UTC)

Origin info

There is little info about the CGRO origin. -- SEWilco (talk) 05:17, 7 December 2007 (UTC)

yes - Could have history section - could say when during development Compton was added to the name. - Rod57 (talk) 14:51, 2 April 2021 (UTC)

Layout problem

Instruments
Instrument	Observing
BATSE	0.02 - 8 MeV
OSSE	0.05 - 10 MeV
COMPTEL	0.75 - 30 MeV
EGRET	20 - 30 000 MeV

The table to the right looks terrible placed on the left. (In the article, that is.) Not only does the text wrap awkwardly around it, but the bullet from the start of the EGRET subsection appears inside the table (on my browser, anyway). "What does that dot next to the OSSE frequency range mean?" was my first thought when I saw it. I see from the history that it was originally on the right, but was moved to the left because it clashed with images that had been added later on. I've been bold and deleted the picture of the Shuttle crew, which IMO has no relevance to the subject of this page, and moved the table back to the right. (Actually, I'm not sure if the picture of the Shuttle launch is particularly relevant either, but I left that one in for now.) But maybe someone with more knowledge of wiki formatting can think of a more robust solution...? 79.72.182.234 (talk) 23:49, 23 October 2017 (UTC)

There was a TDRS Ground Terminal Constructed in Canberra, Australia in 1992 to Receive GRO Data after the Tape Recorder Failures

One interesting aspect of the history of the Gamma Ray Observatory that I don't see mentioned in the main article is that in addition to the TDRS Ground Terminals in White Sands (WSGT), the Second TDRS Ground Terminal (STGT) which were receiving TDRS data from GRO, there was a third TDRS Ground Terminal called the GRO Remote Terminal System (GRTS) that was specifically built in 1992 to provide coverage for the Gamma Ray Observatory (GRO) after its tape recorders failed and there was a requirement to close the Zone of Exclusion (ZOE) to provide continuous real time coverage for GRO.

The decision to build the ground station and devote a TDRS to the Compton GRO came after the observatory's tape recorders failed, restricting transmission of scientific data to real time only. Since Compton was compatible with TDRS, this ground station option was feasible. An on-orbit repair of Compton GRO was an alternative, but would have been much more costly.

"While the new ground station is devoted to Compton at this time, it has the potential for use by other Earth-orbital spacecraft. The TDRS system was designed to operate with all the TDRS spacecraft in view of a single ground station. As a result, coverage could not be provided in a small region on Earth -- the so-called Zone of Exclusion over the Indian Ocean.

"With activation of this ground facility, the TDRS system can, for the first time, provide global coverage," said Charles Force, Associate Administrator, Office of Space Communications, NASA Headquarters, Washington, D.C.

Work on the station was completed in a relatively short time and within its $12 million budget. Work began in September 1992 to implement a remotely controlled terminal at an existing NASA site and was a cooperative effort between the Australian Space Office and NASA

"We're very pleased that this project came in on budget and on time and that we are able to collect additional significant data from Compton in a cost-effective manner," said Frank Stocklin, Head, Radio and Frequency Interface and Mission Analysis Section, Goddard Space Flight Center (GSFC), Greenbelt, Md.

With GRO tape recorders not working, the observatory had been able to relay only slightly more than half of the science data it collected, because it could not point at a TDRS at all times. While coverage had been about 65 percent of each orbit, scientists could not collect that percentage of data because Compton's instruments had to be turned off during the part of the orbit when the spacecraft passed through the background radiation caused by the South Atlantic Anomaly.

"That had represented a significant obstacle to the scientific teams, even though we have been able to collect more science than expected," said Goddard's Dr. Neil Gehrels, Compton Project Scientist. "Now with the ground station and the TDRS, we're back where we want to be."

With a TDRS devoted to Compton, scientists will be able to collect about 30 percent more science. In addition, engineers will be able to keep better tabs on the health of the $500-million observatory, launched from the Space Shuttle Atlantis (STS-37) on April 5, 1991.

"It's difficult to place a dollar value on the additional science data obtained in this effort," Stocklin said, "but the restoration of data recovery capability is similar to that done for the Hubble Space Telescope and marks the second successful recovery of a major NASA observatory."

TDRSs receive data from Earth-orbiting satellites and re- transmits the data to a ground terminal in White Sands, N.M. Data from the Compton will be relayed from TDRS-1 to Tidbinbilla to an Intelsat satellite to a West Coast location and then routed to White Sands. Data then will be distributed to scientists around the world. Control of TDRS-1 and this highly automated ground terminal remains at White Sands, N.M., marking the first time NASA is controlling an out-of-view TDRS from that location.

Launched in 1983, TDRS-1 was the first satellite in the TDRS system and was operating beyond the end of its design life of 8 years when it was moved over the Indian Ocean. TDRS-1 had been located at 171 degrees west longitude over the Pacific. It is now at 85 degrees east longitude, in view of the Tidbinbilla ground station.

"In its current use, TDRS-1's useful life may be extended to the end of the decade and perhaps beyond," Stocklin said.

Here is the official NASA Press Release:

March 1994 - Gamma Ray Observatory Remote Terminal System (GRTS) Declared Operational The Gamma Ray Observatory Remote Terminal System (GRTS) was operational. After the recorders failed onboard the Compton Gamma Ray Observatory (CGRO) in 1992, engineers tried to find solutions to minimize further data loss. Engineers looked to the Deep Space Network complex in Canberra, Australia to locate new TDRS antennas. Equipment was transferred from other facilities and hardware was bought using off the shelf designs. As the building was underway, TDRS-1 was drifted over the Indian Ocean in late 1993. When the system was completed, TDRSS had worldwide coverage. CGRO scientists saw a 30% increase almost overnight. The real time data also identified a unique science opportunity since gamma ray bursts could be disseminated quickly to science observatories on the Earth (and space) enhancing science observations. This approach was used in a number of future gamma ray missions including SWIFT and GLAST. GRTS paved the way for permanent worldwide TDRS coverage. This station was subsequently modified to close the ZOE for the Space Shuttle.

I will leave it to others to decide how much of this information to incorporate into the main article. - 2600:1700:DC50:5560:98AD:A32E:5CBB:3C89 (talk) 06:22, 9 November 2020 (UTC)

Very interesting and worth incorporating. I've made a brief mention in a new History section. More on "An on-orbit repair of Compton GRO was an alternative, but would have been much more costly." would also be interesting - presumably a special shuttle mission. - Rod57 (talk) 15:12, 2 April 2021 (UTC)