At 12:09 PM 5/30/2008, Ronald Nutter wrote:

How about one step further - Maybe they can "pick up" AO-40 and bring it back for a repair job ?

That would be extremely tricky. I haven't done the sums, but there is a significant difference in velocity between AO-40 at perigee and a LEO. However, the delta-V required would be well beyond the Shuttle's capabilities (Ever seen a Shuttle launched into GTO?). Assuming someone had the money to pay for AO-40's return, you'd require some propulsion unit sent up to slow it down and circularize the orbit (possibly with the assistance of aerobraking over a period of time), before you could organise a Shuttle flight to pick it up. Given the cost and the number of unknowns (like how safe would it be to carry AO-40 back, given we have no idea of its condition except that it's up there somewhere), I'd say the odds of this happening are essentially zero.

Interesting "thought experiment" though. :)

73 de VK3JED http://vkradio.com

At 12:15 AM 5/31/2008, Edward Cole wrote:

Once you total the costs it may actually be cheaper to build a new satellite and launch it! Back the effort for P3E and Eagle/P4.

That too, yes, a new bird would be the easiest approach indeed. Still, as I said, it was interesting contemplating how such a recovery might be achieved with today's technology. :)

73 de VK3JED http://vkradio.com

The Shuttle doesn't have nearly the propellant capacity to match speeds with AO-40, even if it were in the same orbital plane. To capture AO-40, it would need to match AO-40's orbit. Just to get into the elliptical orbit and decrease the inclination to 7-degrees is well more thrusting (delta-V) capacity than the Shuttle has. Just to put it into perspective it would need:

1. Maneuver from a 400-km circular orbit to produce a 1200-km apogee (to match AO-40's perigee) -- needs ~211 m/sec of delta-V 2. To perform an apogee boost to match AO-40's semi-major axis and eccentricity (1200 x 58600-km) -- needs ~2660 m/sec of delta-V. 3. To perform an apogee plane change would require at minimum a 21.5-degree inclination, were the Shuttle launched into its minimal 28.5-degree inclination. The delta-V for the minimal apogee inclination-only change would need ~427 m/sec. For the 51.6 degree ISS inclination (44.6-deg change), the delta-V would be ~905 m/sec. 4. Perform terminal rendezvous and capture maneuvers - small in comparison to the others, so I'll call it free. 5. After capturing AO-40, the Shuttle would need to de-boost to a low-Earth orbit (LEO), which requires a perigee braking thrust of another 2660 m/sec. 6. The Shuttle would then need enough delta-V to de-orbit.

The minimum delta-V in the [optimistic] profile I've described would be 211 + 2660 + 427 + 2660 = 5958 m/sec, plus de-orbit delta-V. That's a significant percentage of what it took to put it in orbit to begin with and it still would need enough delta-V to de-orbit. One more piece of bad news: the astronauts would need to fly through the intense radiation environment that AO-40 orbits and remain there long enough to perform the maneuvers I've described and capture AO-40. That would be a serious health risk at the very least.

I think you'll agree, after looking at the numbers, that this suggestion is not feasible.

73, Ken Ernandes N2WWD

-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ransom, Kenneth G. (JSC-OC)[BAR] Sent: Thursday, May 29, 2008 10:11 PM To: w7lr[email protected]; AMSAT-BB Subject: [amsat-bb] Re: Shuttle question

A few extra pounds could be accommodated on the shuttle if you can get high enough on the priority list. Much of that space is reserved for critical components (things so big that only the shuttle can get them there) needed for ISS. Right now, there are only 11 more shuttle flights (including the one scheduled to launch this Saturday, May 31) and a couple of those may go away with the shuttle retirement set for 2010. Getting something boosted higher would take quite a few more pounds, volume and crew time. The greatest challenge is getting through the human spaceflight certification criteria.

It might be worthwhile to explore some of the other launch vehicles that are a bit less constrained time wise (Progress, HTV, ATV and COTS) and see if a piggyback payload could be attached and later boosted. It will still cost plenty unless the payload has a bank rolled primary objective and amateur radio happens to fit in the gaps of the design.

Maybe all of the AMSAT's could buy a Progress after it has served it's purpose and have the Russians boost it to a higher orbit instead of ditching it afterwards. It comes with solar cells pre-installed ;)

Kenneth - N5VHO

________________________________

From: amsat-bb-bo[email protected] on behalf of [email protected] Sent: Thu 5/29/2008 7:03 PM To: AMSAT-BB Subject: [amsat-bb] Shuttle question

Hello I'm sure this question has been bounced around the BB in past. I simply don't recall (senior moment) the results. With all the TONS of stuff they regularly pack up there, it seems logical (another senior moment), that an extra few pounds wouldn't even be noticed, maybe even more than a few pounds. Then we can figure a way to get it even higher than the ISS. Just thinking of a way to get more of a foot in the shuttle door. 73 Bob W7LRD Seattle

-- "if this were easy, everyone would be doing it" _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

_______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb