NASA Press Conference LIVE THREAD

Fox, CNN, networks, NASA TV | February 2, 2003 | NASA

[fooman]

Thanks for your feedback on Ron. What do you think would make a good shuttle replacement? X33 or is there something better?

I had just read that the X-33 was 85% complete when the budget was pulled. I don't know why we pulled this when we could have at least tested one of these to learn more about shuttle flight.

[r9etb]

They should have put up an incentive award to private corporations. Say 500 million, the problem would have been solved long ago.

Of course, that is precisely how they got the current tile design. And when all is said and done, it's actually a pretty decent solution. Light, repairable, and unquestionably effective.

The alternative to tiles would be a "thermal blanket" design, which sounds good until you have to repair it -- not to mention paying for it.

Or an ablative design, which would have to be replaced every flight, at great expense in both time and money.

[r9etb]

I had just read that the X-33 was 85% complete when the budget was pulled. I don't know why we pulled this when we could have at least tested one of these to learn more about shuttle flight.

IIRC, they were having serious delays and cost overruns on the propulsion system. That remaining 15% was 90% of the problem....

I don't know what the best Shuttle replacement would be. The answer to that question lies in what you really need to do. Is there really a need for a reusable spacecraft? If so, is there a crying need for one with a 50,000 lb payload capacity? How much of the Shuttle mission can be transitioned to the ISS? How much of it can be handled by big dumb boosters and one-shot manned capsules?

I think it's possible to build just about anything we need to build. The hard question is what you need, and whether you really need it.

[fooman]

I guess the genrally accepted needs are:

50,000 lb payload and reusablity and horizontal landing.

[r9etb]

I guess the genrally accepted needs are: 50,000 lb payload and reusablity and horizontal landing.

For the first, I think if you measured certain military satellites, you'll find that they just fit into the cargo bay. This is not an accident.

Military launches are now on expendables -- the Shuttle was too expensive, time-intensive, and too susceptible to significant delays due to mission failures, so that requirement no longer exists.

The ISS could be used for spacehab-type missions.

Cargo launches could be done Russian-style, as could the ferrying of astronauts: both use expendables. (I think, however, that we would want to land a bit more gracefully than the Russians do....)

The current Shuttle missions can for the most part be covered by expendable systems.

So the question is: is there really a requirement for reusables? I think there probably is -- the Shuttle is an incredibly flexible spacecraft. It's used for rendezvous, space and earth observation, satellite repairs, and a variety of other things, including ferrying crews and materials to and from ISS.

But I think those missions can likely be done on a much smaller platform.

[fooman]

Our program was going to use the SLD, but your right, we used something else instead that was expendable.

I know there was a drive to make birds smaller like our clementine mission, but not all birds can be made small.


I also think that horizontal take off and landing on some kind of ramjet platform would be cool, if it could made to work technically and economically

[Jael]

It's a quote from the guy who investigated the Columbia foam problem.

[Jael]

I don't have any thoughts about asbestos whatsoever. I do however think it is highly suspicious that the foam begin having this problem when they took the freon out to make it more enviroment friendly.

And they already had proof that the foam coming off on ascent damaged the tiles, and not just a little bit.

Read the reports from NASA.

"According to NASA, during several previous Space Shuttle flights, including the shuttle launched Nov. 29, 1998, the shuttle external tank experienced a significant loss of foam from the intertank.
The material lost caused damage to the thermal protection high-temperature tiles on the lower surface of the shuttle orbiter." http://www.arnold.af.mil/aedc/newsreleases/1999/99-041.htm

As soon as the orbiter was approached, light spots in the tiles were observed indicating that there had been significant damage to the tiles. The tiles do a fantastic job of repelling heat, however they are very fragile and susceptible to impact damage. Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal". The pattern of hits did not follow aerodynamic expectations and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached.Over one hundred (100) tiles have been removed from the Columbia because they were irreparable. The inspection revealed the damage, now the "detective process" began.

During the STS-87 mission, there was a change made on the external tank. Because of NASA's goal to use environmentally friendly products, a new method of "foaming" the external tank had been used for this mission and the STS-86 mission. It is suspected that large amounts of foam separated from the external tank and impacted the orbiter. This caused significant damage to the protective tiles of the orbiter. Foam cause damage to a ceramic tile?! That seems unlikly, however, when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential.

http://ltp.arc.nasa.gov/space/team/journals/katnik/sts87-12-23.html

[Jael]

BTW, the NASA page that had that report about taking the freon out is not opening now.

I don't know why.

Here is a link to a page that mirriored it.
http://www.geocities.com/Heartland/2121/used_news.htm

[Jael]

I don't think it was ice. It was insulation. Also, now the page from Greg Katnik will not open. It was a NASA page which outlined the foam changes and problems.

[Stefan Stackhouse]

The hard surface of the tile is barely thicker than paint and can be damaged by a quarter dropped from 2 feet. Glancing blows are far more forgiving.

And what kind of damage could a direct collision with orbiting "space junk" do? Don't you think it is rather odd that this is a hypothesis that NOBODY has mentioned anything about?

[Jael]

That's the point John. The tiles do fine until they are damaged. The damage doesn't start showing up until the foam insulation starts pinging it. The insulation doesn't start falling off in big chunks like that until they change the formula and take out the freon!!!!

"December 23, l997


Immediately after the Columbia rolled to a stop, the inspection crews began the process of the post flight inspection. As soon as the orbiter was approached, light spots in the tiles were observed indicating that there had been significant damage to the tiles. The tiles do a fantastic job of repelling heat, however they are very fragile and susceptible to impact damage. Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal". The pattern of hits did not follow aerodynamic expectations and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached.Over one hundred (100) tiles have been removed from the Columbia because they were irreparable. The inspection revealed the damage, now the "detective process" began.

During the STS-87 mission, there was a change made on the external tank. Because of NASA's goal to use environmentally friendly products, a new method of "foaming" the external tank had been used for this mission and the STS-86 mission. It is suspected that large amounts of foam separated from the external tank and impacted the orbiter. This caused significant damage to the protective tiles of the orbiter. Foam cause damage to a ceramic tile?! That seems unlikly, however, when that foam is combined with a flight velocity between speeds of MACH two to MACH four, it becomes a projectile with incredible damage potential. The big question? At what phase of the flight did it happen and what changes need to be made to correct this for future missions? I will explain the entire process.

The questions that needed to be answered were:

* what happened?
* what phase of flight did it happen in?
* why did it happen?
* what corrective action is required?

At this point, virtually every inch of the orbiter was inspected and all hits were documented and mapped to aid in visualizing the damage. Maps were constructed of the lower surface, the left and right surfaces and the top surface of the orbiter. At this point, a "fault tree" was created. The fault tree provides a systematic approach in considering all possibilities of what may have happened. Everything that is on the fault tree is considered to be legitimate until it is totally ruled out. Some of the considerations were where the damage occurred -- in the OPF, in the VAB, or on the pad before launch. These were quickly eliminated because an inspection at T-3 ("t minus three") hours takes place on each mission and everything was normal. After these and many other considerations were eliminated, the focus was placed on the ascent, orbit and re-entry phase of the mission. Because of the fore and aft flow characteristics of the damage sites, and the angle of penetration, the ascent phase seemed most likely. The orbit phase of flight was eliminated because the characteristics of these types of hits (most likely meteorites or space debris) occur in a random pattern and direction. Re-entry was eliminated because the "glazing and re-glassifying" of the tiles due to heat upon re-entry (a normal process) indicated that the damage had occurred prior to this phase. The fault-tree was now pointing to the ascent phase.

The pictures that were taken by cameras mounted in the orbiter umbilical began to give the first clues. These cameras are designed to turn on during the solid rocket booster (SRB) separation, and turn off after the separation is complete, thereby recording the event. This process occurs once again when the external tank separates from the orbiter. The initial review of these photographs did not reveal any obvious damage to the external tank. No foam missing, no "divots" (holes) and no material loss.Everything appeared normal. The SRBs were then focused on for the answers. After inspection of the SRBs, no clues were found. In fact, the solid rocket boosters looked to be in great condition. Where to now? The external tank photographs were magnified and reviewed once again. This time some material loss was noted, but not in a significant degree. The attention was now focused on the crew cabin cameras. These cameras gave more of a side view of the external tank as it tumbled back to Earth. These photographs revealed massive material loss on a side of the external tank that could not be viewed by the umbilical cameras!

Where did that leave us? One of the questions had now been answered. The ascent phase of flight was when the damage occurred. With the information provided by the photography and the mapped flow of damage, a logical reason could be established as to "what" happened. It was determined that during the ascent, the foam separation from the external tank was carried by the aerodynamic flow and pelted the nose of the orbiter and cascaded aft from that point. Once again, this foam was carried in a relative air-stream between MACH 2 and MACH 4!

Now the big question -- why? The evidence of this conclusion has now been forwarded to Marshall Space Flight Center (MSFC) because this is the design center for the external tank. MSFC will pursue the cause of damage. Here are some descriptions of some of the possible causes:


POSSIBILITY 1
The primer that bonds the tank foam to the metal sub-stream was defective and did not set properly. This was eliminated as a cause because the photography indicated that the areas of foam loss (divots) did not protrude all the way down to the primer.


POSSIBILITY 2
The aerodynamics of the roll to "heads up." The STS-87 mission was the first time this maneuver had ever been completed.


POSSIBILITY 3
The STS-86 mission revealed a similar damage pattern but to a much lesser degree than STS-87. The STS-86 tile damage was accepted ruled as an unexplained anomaly because it was a night launch and did not provide the opportunity for the photographic evidence the STS-87 mission did. A review of the records of the STS-86 records revealed that a change to the type of foam was used on the external tank. This event is significant because the pattern of damage on this flight was similar to STS-87 but to a much lesser degree. The reason for the change in the type of foam is due to the desire of NASA to use "environmentally friendly" materials in the space program. Freon was used in the production of the previous foam. This method was eliminated in favor of foam that did not require freon for its production. MSFC is investigating the consideration that some characteristics of the new foam may not be known for the ascent environment.

POSSIBILITY 4
Another consideration is cryogenic loading, specifically hydrogen (-423 degrees Fahrenheit) and oxygen (-297 degrees Fahrenheit). These extreme temperatures cause the external tank to shrink up to six (6) linear inches while it is on the pad prior to launch. Even though this
may not seem much when compared to the circumference of the external tank, six inches of shrinkage is significant.

This is where the investigation stands at this point in time. As you can imagine, this investigative process has required many hours and the skills of many men and women dedicated to the safety of the shuttle program. The key point I want to emphasize is the PROCESS OF INVESTIGATION, which is coordinated amongst many people and considers all possibilities. This investigation has used photography, telemetry, radar coverage during the launch, aerodynamic modeling, laboratory analysis and many more technical areas of expertise.

As this investigation continues, I am very comfortable that the questions will be answered and the solutions applied. In fact, some of the solutions are already in progress. At present the foam on the sides of the tank is being sanded down to the nominal minimum thickness. This removes the outer surface, which is tougher than the foam core, and lessens the amount of foam that can separate and hit the orbiter."

[Not now, Not ever!]

As for the last possible moment of aborting, I'm not sure of the specific altitude, but I do know that depending on where they are in the launch phase they have several airports around the world where they can land if they have to punch off the external fuel tank before they achieve orbit.

I think one aditional problem would be, How much time do you have to make the decision to abort the climb to orbit? If you are un-aware of damage during boost, Why would you abort the climb? Once on orbit you are committed to a re-entry. Sort of a catch-22.

[Stefan Stackhouse]

Actually the tile problems are over 22 years old.

The choices are:

1. To replace them with something else (cept their isn't anything else).

2. Carefully manage their known issues (which we have done for 113 flights)

3. Stop flying (any other vehicle would have to use similar tiles)

I can think of a 4th option:

4. Use a smaller vehicle, one designed to transport a human payload only, and leave the bulk cargo hauling to large unmanned rockets; smaller vehicle = fewer tiles = fewer possibilities of tiles being damaged.

[WFTR]

There is NO negligence here. 17 loses in 40 years is a good record. NASCAR can't match it.

I should have given more than a one-line answer to the previous post, but you completely misunderstood what I was saying. The post to which I was referring said that it was incompetent to know of the problem of the insulating foam coming off the engines for five years and not to take any action to fix it. When I called refusal to address the problem "willful negligence," I was using the term as it is used in most of American industry. I work in the petrochemical industry, and if we knew of a potentially life-threatening situation and refused to address it for five years, we could be jailed for willful negligence if the situation resulted in someone's death.

I don't know whether NASA was trying to address the situation or not. If they were and simply hadn't found a good fix, then "willful negligence" does not apply. Maybe incompetence is an issue, but I am more inclined to believe it is just one of the problems with space travel. As I understand what has been said in this thread, the foam insulation falling from the booster is a problem that is about five years old and caused by the change from fluorocarbons to some other gas in the making of the insultation. Both my comments and the comments that preceded them need to be remembered in that light.

I still support the space program and understand that the thermal tiles are the best solution that we have so far to a difficult problem. As far as I know, we still can't be certain that Saturday's disaster was caused by tile failure anyway. I've done enough failure analysis to understand the need not to analyze ahead of the data. It's easy to blame things on a known weak link, but sometimes the real cause of failure was something entirely different.

I realize that space travel is different from the rest of American industry, but 17 losses in 40 years is not considered good outside of things like NASA and NASCAR. In the petrochemical industry, our risk analyses must show an expected death rate of less than one death in 10,000 years in order to accept a situation. We have accidents that no one expects and have a higher rate, but 17 in 40 years would be considered very bad.

WFTR
Bill

[BurbankKarl]

there are radioactive pieces with the shuttle


>>>but I'm having trouble understanding the toxicity thing
There is no hazard. They just want to scare people into staying away from it.

[BurbankKarl]

tben you ask your crew who wants to sack out on the ISS a few months, and who wants to come back to earth....


>>>They had 16 days up there, they should have spacewalked around the shuttle to check for damage
And then...?

Buy a clue.

Repair was not an option.

[John Jamieson]

You can't compare the world's highest performance aircraft/spacecraft with anything on earth. We make progress only by pushing the envelope.

We have never even created a new high performance airplane without killing a test pilot.

Your risk aversion is not the same as astronauts and race car drivers; they fight for a chance to go.

[John Jamieson]

It's available now, go for it, NASA will pay.

Why do people who know nothing about a subject, assume that those that do are idiots?

PS: the tile WAS developed by a private company.

[John Jamieson]

I was very impressed. Ron makes the Eron type leaders look like total idiots.