Robotic spacecraft mission cut short

[gfpaladin]

By Beth Dickey<br /><br />An apparent fuel shortage brought a government space technology demonstration to a premature end in Earth orbit late Friday. <br /><br />The $110 million robotic spacecraft, known as Demonstration for Autonomous Rendezvous Technology, was designed to test autopiloted rendezvous techniques for U.S. civilian and military space vehicles. It stopped operating less than 24 hours after it was launched from Vandenberg Air Force Base in California. <br /><br />NASA, which sponsored the mission, said it is convening a mishap investigation board. <br />

 

[grooble]

Where can i get blue prints and specs for the DART ship? Is it legal to have them?<br /><br />I want to use the technology in my space taxi, due to go online after 2020 but no later than 2040.

 

[mrmorris]

<font color="yellow">"Where can i get blue prints and specs for the DART ship?"</font><br /><br />You can't. They'll be classified at the moment. In 30-ish years, they'll probably be available just as the Apollo/Gemini/etc. docs are now. You can view some fact sheets about DART here if you'd like.<br /><br />In any event -- the DART tech would be relatively useless for a concept such as your taxi. The DART had essentially three basic autonomous navigation 'items' that I know of off the top of my head. <br /><br />1. GPS navigation. DART used it's own GPS data plus that of the target to maneuver within visual distance (I forget the visual aquisition range). GPS will be of marginal use to a lunar taxi. The taxi will need to have at least one system to supplement GPS once that system is no longer applicable -- most likely a stellar tracker.<br /><br />2. Visual guidance. DART used the Advanced Video Guidance System (AVGS) to perform close-in maneuvers around the target. It required that the target be equipped with identification markers for the software to work from. <br /><br />3. Autonomous programming. The programming which actually allowed DART to function without human assistance is likely the most valuable thing about it. However, for one -- DART failed -- very likely because the navigation program was using too much threust (possibly lots of corrections, overcorrections, etc.), and for another -- it was a very low-powered system (cold gas thrusters), and would be only marginally applicable to a larger craft that used higher-powered thrusters. The navigation software was also designed for a *very* specific purpose, and would not come anywhere close to meeting the needs of the craft you envision.<br /><br />The other autonomous craft that the Air Force launched XSS-11 (I think) would actually be a better match. It's supposed to approach several <b>unprepared</b> target

 

[tap_sa]

What's the best place to dig up NASA documents that are available to the public? Some NASA site obviously but where there, it's such a mess I've never found much anything, just mundane K-12 stuff. I'm especially interested in some documents called SP-xxxx (four digits), SP-8xxx documents supposedly contain a lot of 60s rocket tech info. Old stuff but most of the facts aren't out of date.<br /><br />

 

[grooble]

Yes i was thinking about a stellar tracker. I'm sure you could put sensors on the craft so it knows it's precise 3d position within the earth moon system. <br /><br />http://www.llnl.gov/sensor_technology/STR45.html would something like this suffice?

 

[mrmorris]

The NASA Technical Reports server is here. I'm not too impressed with its search interface, though. It's fine if you know just what you're looking for, but not so hot if you're just fishing.<br /><br />I have gotten most of my docs on manned spaceflight from here.

 

[mrmorris]

<font color="yellow">"...would something like this suffice?"</font><br /><br />Most likely. There's half a dozen star trackers out there. I haven't really researched them because I haven't had any reason to. I just run across them on occasion when I'm looking up specs on equipment for G-X3.