nickw@syma.sussex.ac.uk (Nick Watkins) (05/01/91)
I noted in a recent item in the UK Daily Telegraph newspaper that Endeavour carries a "navigation system used in the Gulf War". I take this to be GPS. Am I correct in this ? If so: 1) Why didn't previous shuttles carry it ? 2) Do other spacecraft use GPS ? Was it part of ASAT designs, for example ? 3) Is it precise enough to locate spacecraft *relative to each other* to order km. This would have been a real asset to ESA's cluster project, I'd have thought, but apparently interspacecraft tracking is all ground based. Nick --
henry@zoo.toronto.edu (Henry Spencer) (05/01/91)
In article <4975@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes: >Endeavour carries a "navigation system used in the Gulf War". I take >this to be GPS. Am I correct in this ? It's about the only thing it could be. >1) Why didn't previous shuttles carry it ? The existing shuttle orbiters are all nearly ten years old, and the design is even older. Navstar, aka GPS, has become semi-operational only quite recently. >2) Do other spacecraft use GPS ? Was it part of ASAT designs, for >example ? I don't think any of the flown Asat designs used it. I'm not immediately aware of any current satellites using it, although there might be a few doing it experimentally. There is much interest in the idea. >3) Is it precise enough to locate spacecraft *relative to each other* to >order km. This would have been a real asset to ESA's cluster project... It should be precise enough, but bear in mind that it won't work for anything much beyond low orbit. -- And the bean-counter replied, | Henry Spencer @ U of Toronto Zoology "beans are more important". | henry@zoo.toronto.edu utzoo!henry
nickw@syma.sussex.ac.uk (Nick Watkins) (05/02/91)
From article <1991May1.162616.16919@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): >>1) Why didn't previous shuttles carry it ? > > The existing shuttle orbiters are all nearly ten years old, and the design > is even older. Navstar, aka GPS, has become semi-operational only quite > recently. True, but Navstar itself dates back at least to mid 70s in design (I had descriptions of it from USAF in late 70s), and it was expected to become operational rather earlier than now, was it not ? Nick --
jandres@sag4.ssl.berkeley.edu (Jeff Andres) (05/04/91)
The first NASA satellite to use or experiment with GPS is a satellite known as the Extreme Ultraviolet Explorer. It is going to be a peripheral experiment attached. This is documented in I believe the March issue of GPS World magazine. I also know about this because the instrument on EUVE was built by UCB and I am the Science Operations Manager for the mission. Hope this helps. BTW, Motorola built the GPS receiver. _________________________________________________________________________ ^ _____________ ^ ^ | | Jeff Andres ^ ^ | | jandres@ssl.berkeley.edu ^