semi-down ISS and ESAS News from AW&ST

[radarredux]

The March 5, 2007 issue had a few data points in their articles that surprised me. I thought I would send them out for comment.<ul><li>A safety task force on ISS estimated that with the current design, the ISS has an 18% chance of debris impact forcing it to be abandoned, and a 9% that it would lead to loss of life. (Adding more shielding would lower those numbers).<br /><li>Even with Progress, ATV, and HTV there is a significant shortfall in logistics support to ISS.<br /><li>The panel believes the COTS efforts will take longer than expected and cost more than anticipated.<br /><li>The panel believes NASA should allocate another $1 billion per year to ensure adequate logistics and spare parts for the station.<br /><li> "the Congressional Budget Office (CBO) has calculated a saving of $16 billion through 2012 if Congress puts off the deadline for returning to the Moon by five years--to 2025. But the CBO notes one 'drawback' to the option--it would extend the gap 'to almost a decade.'"</li></li></li></li></li></ul><br />What bothers me are (1) if NASA does need to allocate an additional $1 billion per year to support the ISS, it will probably come out of the ESAS program (which would push back the Moon effort even more), and (2) just suggesting pushing back the Moon program to 2025 to save $16 billion scares me. Some in Congress may jump on that to fund or save their own special programs.<br /><br />I am concerned that the goals of landing on the Moon (2018-2020) and establishing a serious outpost there (~2024-2025) are so far out in time (at least 6 congressional elections and 3 presidential elections), that very few in Congress may see any advantage for voting to protect that money for that future goal instead of spending it on something more immediate.

 

[trailrider]

It would not surprise me in the least if the return to the Moon slips due to budgetary shortfalls...UNLESS it becomes obvious that our astronauts will have to learn Cantonese and apply for a Chinese passport to land! I'm being somewhat facetious, but IMHO there is a good chance that the PRC is pressing ahead, not recklessly, but persistantly. If they appear to be closing the gap between the U.S.A. and Russia, and/or if India also begins a manned space program, some sort of co-operating between countries OTHER than the U.S. may happen. If so, hopefully, Congress, pushed by American outrage will ante up and kick in. There ARE those members of Congress who are alarmed by the apparent gap between the phase-out of Shuttle and the IOC (initial operational capability) of Constellation systems.<br /><br />At least I hope so!<br /><br />Ad Luna! Ad Ares! Ad Astra!

 

[JonClarke]

Over what sort of time frame are those probabilities calcuated? What assumptions were used?<br /><br />They seem very high, given the fact that despite more than four decades of space station operation there has not been one instance of serious damage from orbital debris.<br /><br />For comparison, assuming the chance of a shuttle fatality is 1/100, the probability of another fatal shuttle accident in the remaining 14 missions is 13%.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[radarredux]

> <i><font color="yellow">Over what sort of time frame are those probabilities calcuated? What assumptions were used?</font>/i><br /><br />I believe the 18% & 9% numbers (abandonment & death) were through the nominal end of the space station service life of 2016 (the date the panel used). Installation of debris shields on the Zvezda service module would drop those numbers to 14% & 8%. Adding additional debris protection to Progress and Soyuz vehicles would lower the figure to 8% & 5%.<br /><br />As a counterpoint, Griffin recently stated (NY Times Article) that the on any given day there was a 1 in 100,000 chance that the station will be critically damaged by debris. Running this out over 10 years, I get something like a 3.4% chance of ISS being critically damaged by debris.<br /><br />The AW&ST article is "Safe in Space: Panel cautions against dangers in post-shuttle ISS operations", by Frank Morring, Jr.<br /><br />The AW&ST article on ESAS and CBO numbers is "Gap Filler" in the Washington Outlook section.</i>

 

[JonClarke]

I would think not. Not only are the "pieces" larger, they move at relative velocities orders of magntiude less than true debris.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[vulture2]

>>>What bothers me are (1) if NASA does need to allocate an additional $1 billion per year to support the ISS, it will probably come out of the ESAS program (which would push back the Moon effort even more),<br /><br />I agree. That's why the original VSE plan anticipated dropping the ISS. If we are not prepared to either drop ISS or raise taxes, VSE (at least the lunar missions) is not affordable. The operational cost estimates in the ESAS and LSAS are unfortunately not realistic. The vehicles currently planned for the VSE are designed to maximize use of "existing resources". This may lower development cost. But in return, just as with the Shuttle, they will demand an operating cost that is simply not sustainable.<br /><br /> />>UNLESS it becomes obvious that our astronauts will have to learn Cantonese and apply for a Chinese passport to land! <br /><br />There is no indication that China will be so foolish as to engage in a new race to the moon. They would have nothing to gain and much to lose. Even if they landed first they would be jeapardizing relations with their largest customer, the US. China's human spaceflight program is intended to enhance its national image and promote its technology and commercial space capabilities. Consequently they plan a relatively low flight rate which will permit at least one new achievement per year for an indefinite period. <br /><br />An alternative approach would be a cooperative program with China. Inviting them to join the ISS program would be a logical start; China is the only country not now in the program which could contribute significant logistic capability. However this is unlikely in light of the inexplicable rejection by the NASA Administrator of an invitation to tour the Chinese launch site. <br />

 

[vogon13]

What really annoys me about the lack of a robust debris shield for the ISS is that for virtually no cost at all (relative to what was spent on ISS) they could park some shuttle external tanks along the most likely vectors for incoming junk.<br /><br />A shuttle ET would make a great 'barrier' and could even be monitored with a piezoelectric detector to record impacts.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[MeteorWayne]

Maybe it's just me, but sounds very unwieldly to implement.<br /><br />Also, where do you steal the extra propellant from to get the ET to orbit? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[solarspot]

http://www.permanent.com/p-extank.htm<br /><br />This page suggests getting an ET to the ISS would be feasable... And more discussion is on this site:<br /><br />http://www.orbit6.com/et/

 

[spacester]

The big orange cloud of foam issue is a very real obstacle to the use of SS ETs.<br /><br />SG said that they cannot - with the current shuttle configurations - get the ET to ISS. I have no doubt that the threads you refer to have proposals for other configurations that would enable it.<br /><br />BUT the big orange cloud is almost certain to form and it would be a HUGE problem. If you've followed the shuttle program the last 4 years, you know all about the ET foam and it can be taken as a given that there is NO WAY NASA will make a change to it to accommodate on-orbit ET use at this stage of the game. I *might* have disagreed with that stance 10 years ago, but not now.<br /><br />The opportunity has long since passed. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

The key phrase in my post, <i><b>relative to what was spent on ISS</b></i>, seems to have sailed right over everyone's head.<br /><br />How many shuttle flights to the ISS have been made with a payload weight more than the weight (mass for the harpy purists out there) of the ET <i>less</i> than the 60,000 pound (or whatever the new limit is now) max payload to the ISS altitude?<br /><br />What would a kapton/mylar baggie, Soyuz deployable, sized to fit the ET cost?<br /><br /><i>Compared to the total ISS budget (and don't forget all those multi-billion dollar redesigns Reagan inflicted on the program to save millions of dollars) ?<br /><br /></i> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[scottb50]

I don't see it as that big of a problem. The foam is less dense so would tend to move off, unless it got stuck on something, the impact velocity would be negible anyway.<br /><br />It might cause a problem with the solar arrays, but as it would gradually deteriorate it could be easily dealt with. The mass of the foam would be very low so ISS would be easier to spot, displaying a tail like a Comet. <br /><br />Probably the biggest problem is getting an ET to ISS. The payload would be substantially reduced if not eliminated. I seriously doubt you could even get one there without a Tug. <div class="Discussion_UserSignature"> </div>

 

[solarspot]

While I don't see any real use for the ET as a meteorid shield, If you read either of the two websites I linked to (actual sites not threads BTW) you will see that it is not just possible... but relatively easy to actually get them there.<br /><br />"Probably the biggest problem is getting an ET to ISS. The payload would be substantially reduced if not eliminated. I seriously doubt you could even get one there without a Tug."<br /><br />The Shuttle already carries the tank 99% + the way to orbit... and if the SSME's could actually use the very last couple tonnes of fuel in the tank then the OMS wouldn't need to do an extra apogee (sp?) raising burn (saving fuel for orbit circulization burn and de-orbit), or atleast less of one.

 

[ckikilwai]

How do you imagine this robust shield around the ISS vogon13?<br />Because the modules probably have already some protection, and the shadow of big shields could cause problems to the solar panels.