By Jefferson Morris
Aerospace Daily & Defense Report 2/28/07
NASA has added an unmanned orbital flight of the Orion Crew Exploration Vehicle (CEV) in March 2013 to gather additional data prior to the first manned Orion flight scheduled for that October.
"We wanted to insert an unmanned orbital flight before we put humans onboard," Exploration Launch Manager Steve Cook told The DAILY, Feb. 27. The Orion will be boosted to orbit by the Ares I — a
modified five-segment space shuttle solid rocket booster.
The unmanned orbital test flight will be preceded in September 2012 by a mission dubbed "Ares 2" — a suborbital flight intended to test the Ares I's prototype upper stage as well as the Orion's
launch abort system.
Meanwhile, Ares and Orion engineers continue making progress on keeping system weights within acceptable margins, according to Cook. The most recent weigh-in for the stack took place last week and
"things look good," he said. The Orion had been running roughly 3,000 pounds over its weight target, but the latest baseline design shows "an awful lot of progress" in weight reduction, Cook said.
The first launch of Ares hardware will be the Ares I-X test flight in April 2009, which will be a suborbital mission featuring a dummy upper stage. Cook's office features a clock ticking down the
days to launch — 778 and counting.
Last week NASA kicked off the Ares I upper stage system requirements review (SRR), which will last through April. It will be the last element-level SRR as the Ares team moves from the requirements
phase into the design phase, Cook said. The Ares I's preliminary design review is scheduled for 2008.
NASA is leading the design for the upper stage and plans to select the industry partner that will produce the stage in August. The last major procurement for the Ares I will be the Instrument Unit (IU),
for which a draft request for proposals (RFP) is expected in late April and the final RFP in late May or early June. Award is scheduled for early December.
Roll control
The guidance, navigation and control team for the Ares I is still analyzing data from last November's static test of a four-segment space shuttle reusable solid rocket motor (RSRM) conducted in Utah (DAILY,
Nov. 20, 2006). The booster was instrumented to gather information on how it will perform as a single stick and address concerns about what level of thrust will be required to keep the vehicle from rolling as
it ascends.
The team believes the final analysis will show that they can reduce the amount of roll control authority for the rocket, Cook said.
Keith Stein, Launchspace Editor
http://launchspace.com/articles/ares21607.shtml
Fri Feb 16, 11:40 PM ET —The National Aeronautics and Space Administration (NASA) released an updated draft solicitation on Friday detailing plans for development of the agency's
new Ares I launch vehicle. The Ares I booster is a new launch vehicle NASA is developing to replace the Space Shuttle and to return astronauts to the moon.
The solicitation includes a schedule showing the Ares Upper Stage development milestones including planned launches carrying the new Orion Crew Exploration Vehicle.
"The milestone schedule, per the latest planned manifest, is anticipated to change," NASA said in documents released Friday. "The Upper Stage Development Plan is being updated to reflect
the latest manifest mission dates."
The updated solicitation shows the following changes to the Ares I launch manifest:
- The Ares I launch, planned in June 2011, was removed from the schedule.
- Orion 3 (first human flight) has moved from October 2013 to March 2013.
- Orion 4 mission (IOC) has moved from March 2014 to October 2013.
- Orion 5 mission has moved from September 2014 to March 2014.
- Orion 6 mission has moved from March 2015 to September 2014.
- Orion 7 mission has moved from September 2015 to March 2015.
- Orion 8 mission has moved from March 2016 to September 2015.
- Orion 9 mission has moved from September 2016 to March 2016.
- A new mission, Orion 10, is added in September 2016.
| Upper Stage Element Milestones |
Date |
| Upper Stage Preliminary Design Review |
May 2008 |
| Upper Stage Critical Design Review |
November 2009 |
| Main Propulsion Test Article Activation |
September 2010 |
| Upper Stage Ground Vibration Test Activation |
November 2011 |
| Ares 2 Mission |
September 2012 |
| Upper Stage Design Certification Review |
December 2012 |
| Orion 3 (First Human Flight) Launch |
March 2013 |
| Orion 4 Mission (IOC) |
October 2013 |
| Orion 5 Launch |
March 2014 |
| Orion 6 Launch |
September 2014 |
| Orion 7 Launch |
March 2015 |
| Orion 8 Launch |
September 2015 |
| Orion 9 Launch |
March 2016 |
| Orion 10 Launch |
September 2016 |
NASA Space Flight
By Chris Bergin, 2/6/2007
NASA Constellation have decided to increase the propellant capacity of the Ares I Upper Stage tanks, despite moving to a common bulkhead design — which initially shortened the vehicle
by 60 inches in length.
The latest Upper Stage change returns the vehicle to a previous Design Cycle configuration, while keeping the recent mass saving move to a common bulkhead. These changes are believed to
be responsible for the delay to the completion of the Upper Stage SRR (Systems Requirement Review).
The stretching of the propellant tankage — by about five feet — will increase of the amount of additional capacity in the tanks by an estimated 11,650 pounds, whilst returning to
the length of previous Upper Stage design for the DAC-1C vehicle design.
Previously, the Upper Stage had the following capacities (rounded up):
- LH2 — 74,500 gallons = 44,000 pounds.
- LOX — 25,500 gallons = 242,250 pounds.
- Total propellant = 286,250 pounds.
Now sources estimate that the change to the Upper Stage — with a common bulkhead — will result in the DAC-1C configuration moving to:
- LH2 — 83,200 gallons = 49,000 pounds.
- LOX — 26,200 gallons = 248,900 pounds.
- Total propellant = 297,900 pounds.
The elimination of the intertank from the Upper Stage was initially used to save mass. The decision to instead translate the saving into larger propellant tanks will have a number of
potential benefits. However, it is expected to have a slightly negative effect on the Upper Stage's initial acceleration, reducing it to around 0.6 G.
The Upper Stage SRR conclusion on this current Design Cycle, which was delayed from the start of the year, is now expected to be completed by March at the earliest. The SRR was initially
believed to be delayed due to a potential move to a 6.3 diameter Upper Stage option. That was recently dismissed as an option by Constellation.
"The Exploration Launch Office Chief Engineer, along with polling members of the TIM, recommended going with common bulkhead configuration due to the dry mass savings of 2,165 lbm needed
to close the payload requirement," noted Constellation's Steve Cook.
"On day two of the TIM, the US Chief Engineer presented a Risk assessment for the following three different configurations: Separate Tanks, Common Bulkhead with a 5.5-meter diameter,
and a Common Bulkhead with a 6.3-meter diameter.
"The high risks in performance estimate savings, schedule, and cost supported the TIM recommendation of not going forward with a 6.3-meter diameter design configuration."
At around the same time as Constellation decided on lengthening the Upper Stage, ATK updated their figures that show the predicted weight of the 5-segment Solid Rocket Booster — which
will be the first stage powerhouse for the Ares 1 Crew Launch vehicle — has dropped by around 10,000 pounds over recent months.
By Keith Cowing
Space Ref — Sunday, January 28, 2007
Last week, NASA's Associate Administrator for Exploration Systems Mission Directorate (ESMD), Scott Horowitz, sat down with reporters to discuss the Ares 1 and Orion programs. The impetus for
this briefing, according to Horowitz, were recent stories — of varying accuracy — regarding weight and performance issues.
Background
While internal sources have been talking for months about issues they saw with regard to the ability of Ares I to launch Orion, and Orion's ongoing weight issues, this issue came to a head
on 11 November 2006 when I published a short item on NASA Watch.
Two days later, Constellation program manager Jeff Hanley fired off a hastily written memo. Hanley noted "many who carp from the sidelines do not seem to understand the systems engineering
process. They instead want to sensationalize any issue to whatever end or preferred outcome they wish. So be it, that is the world we live in." He then went on to admit that weight and
performance issues had indeed arisen stating "Both the Ares I performance and the Orion control mass are 'watch items' on our list of top program risks. This is NORMAL for any such development
effort ... mass delivered to space has been and will always be a source of risk for any spaceflight project or program." Hanley closed his memo by sniping at critics: "We will continue to get
these faux expressions of concern from those who wish to see us fail."
NASA followed Hanley's memo with a formal press statement on 16 November 2006 which specifically addressed the issues raised about Ares I performance: "An example of the activity was a review
and analysis that confirmed the planned Ares I launch system has sufficient thrust to put the Orion spacecraft in orbit. In fact, the Ares I thrust provides a 15 percent margin of performance in
addition to the energy needed to put the fully crewed and supplied Orion into orbit for a lunar mission. Engineers established Orion's take off weight for lunar missions at over 61,000 pounds."
On 4 December 2006 I posted an article "NASA To Evaluate Non-recoverable First Stage for Ares I Launch Vehicle" which said that "some of the people working on the design of NASA's new Ares I
launch vehicle want to delete the requirement to recover and reuse the rocket's first stage. The reason: the weight of hardware required to make recovery possible — and practical." A day or so
after this article went online, I asked when I asked ESMD Associate Administrator Scott Horowitz about this issue at the AIAA Second Space Exploration conference in Houston. He did not blink an
eye in responding that the Ares I first stage "will be recoverable".
On 4 January 2007 NASA announced that the Ares I requirements review had been completed, stating: "The system requirements review confirmed that the Ares I system requirements were complete,
validated and responsive to mission requirements. It also confirmed that the Ares I architecture and design concept can fulfill the mission objectives and that the Ares project is ready to begin
engineering design activities. The Ares preliminary design review is scheduled for mid-2008."
On 4 January 2007 NASA also issued a presolicitation notice and a draft RFP for the Ares 1 upper stage. NASA plans to release a final RFP on or about 23 February 2007.
On 8 January NASA announced that was extending ATK's Ares I development contract to continue design and development of the first stage for the Ares I crew launch vehicle. This additional
$48 million in funding was being added to a first stage task under an existing shuttle contract.
Stories have continued to appear in print and online regarding the same issues. In addition, a variety of unofficial alternate launch vehicle concepts have floated around — all with varying
degrees of authenticity and technical validity. As one would expect, Horowitz was somewhat dismissive of these things and stuck firmly to the official launch vehicle development approach NASA
had been following for the past several years.
Overweight or Underpowered?
The main issue that Horowitz has been trying to combat, is the widespread impression that the Ares I cannot launch the Orion spacecraft — especially on lunar missions. The flip side of the
coin is that the Orion's weight has been growing as its design progressed, thus making it harder for Ares 1 to launch. It would seem, based on Horowitz's presentation, that the issue is mostly
driven by Orion weight gains set against a somewhat constrained performace capability of the Ares 1 booster.
Horowitz produced several charts to the reporters present in order to illustrate the status of Ares 1 and Orion development. All spacecraft and launch vehicles are faced with a tendency to
gain weight as requirements are translated into hardware designs. that is a fact of life. At any given time in this process, a snapshot might seem to show that one or more weights are outside
the limits that have been set.
A simple glance at the charts showed that the projected weight of the Ares 1/Orion launch configuration had grown significantly between September and December 2006. This was due to things
being added as the design process progressed. According to Horowitz "52,231 pounds is line that Skip Hadfield has to meet". Getting the overall weight to stay below that line includes all of
the performance reserve or "margin" that Horowitz wants the system to have. Horowitz said that his preferred outcome would be that the Ares 1 would have 13,000 lbs of performance reserve.
Horowitz said "the Ares 1 has more than sufficient performance. The top line is what Ares 1 can deliver to orbit 58,333 pounds for a lunar mission. We have 8,102 pounds of performance reserves.
The effective weight the Ares 1 is lifting has to be under 50,231 pounds. The current design is under that."
Margins, Reserves, and Bookkeeping
As is the case with any large design and development program, there is a tendency to over estimate the margin that other systems may be holding back. Other tendencies include citing margin
in one system as your own, without checking to see if another part of the project is also carrying that margin as "theirs". I asked Horowitz about how such bookkeeping errors were big avoided.
He described a very clear accounting process whereby the Ares 1 and Orion projects were not double counting margin and reserves.
Bookkeeping weight also needs to take into account how long that weight is part of the overall launch equation. In the case of the Launch Abort System (LAS), while it weighs in at roughly
13,400 pounds, it is discarded well before the Ares 1's payload is placed into orbit. According to Horowitz, the "effective" weight of the LAS, when all launch calculations are taken into
consideration, is actually 1,675 pounds. Put another way "If I removed the LAS I'd be able to put an additional 1,675 pounds into orbit" Horowitz said.
According to Horowitz, sources of possible weight savings include the Thermal Protection System, Crew weight, cockpit hardware, avionics and other systems. In addition to design choices,
there are other ways to offset weight — increasing the performance of the Ares 1 propulsion systems.
More power under the hood
One possible change has to do with the composition — and pouring of the solid rocket booster fuel. The current mixing formula is an "old formulation", according to Horowitz, one that has
"nice handling characteristics." The rate at which the fuel burns is the result of the chemical formulation that is used in its mixing. This is something Horowitz said is being looked at for
possible "tweaking" so as to gain some additional performance. Another possible change under consideration would be the geometry of the hollow space in the last (fifth) or uppermost segment
of the first stage of the Ares 1. The change would have to do with the number of "fins" or indentations that are cast into the fuel. The current number of fins (8) might be increased to 12.
This would allow increased surface area, therefore a faster burn, and more thrust at the point in the launch profile where it would be of greatest use.
Another possible performance boost might come from use of the Launch Abort System (LAS). The LAS is designed to pull the command module off of the rest of the launch vehicle — in a manner
similar to that employed on Apollo — in case of an emergency situation. In the option under study, the LAS would be fired — and yet remain attached to the Command Module — (and the remainder
of the launch vehicle) to give a little extra boost during the point in the mission prior to where it would be readied for disposal (around Mach 5). Using smaller rocket engines for additional
propulsion is not a new idea inasmuch as the Shuttle regularly uses its OMS engines to increase overall launch performance. However, the OMS engines are not dedicated aboard and crew escape
system as are those in the LAS.
According to Horowitz the studies showed that you could realize an increased delivery of around 1,000 pounds of payload into orbit. However, the mechanical and structural connections to the
command module that would be required to allow this option to be implemented would eat into that payload boost — by several hundred pounds. Even if this option were to be considered worthy of
the engineering changes, Horowitz seemed troubled by the prospect of using the LAS in a routine launch ascent. "If you fire the [LAS] engine nominally every flight, you have just added another
stage to ascent and therefore decrease the reliability." Horowitz also expressed concern about using a crew safety system for soemthing other than crew safety — that just detracts form the
ability of that system to do its prime task. Although Horowitz would not discount this LAS option out of hand, it was obvious that he was not very enthusiastic about it — but he said that it
was still under study to see "if there is any gold to be mined there."
A better Aim on the way home
Another item under study by NASA - and one responsible for some of the margin that is needed — has to do with reentry. Horowitz said that "skip entry" was being studied as a way to better
control landing site aim — and to make last minute changes if one site becomes unavailable for some reason. Horowitz said that this was an option available — but never used - during Apollo.
In essence, the Command module would enter the Earth's atmosphere, slow down, and then skip out again. After a period of time it would reenter once again and descent to its landing site. The
issue under study is whether the Thermal Protection System's ablation system's chemistry will allow it to go from prolonged cold exposure ("cold soak"), heat up to high temperatures, cold soak
again, and then be reheated.
During the flight testing phase of Orion's development , flights, some of then unmanned, will be flown to test various systems. One thing Horowitz said would likely be done is to fly a
mission whereby the Command Module's head shield is tested at the speeds expected during a return form the moon. One way to do this might be to launch an unmanned Command Module, with out
an escape system (to save weight) and put in as much fuel as possible. Something like this was done on Apollo 4 and was planned for Apollo 6.
Another option that might be available (based on a study done at MSFC) would be to use some Ares 1 components and some Ares V components. When I asked Horowitz about the rumored "Ares IV"
he replied that some ideas had been studied (although he refrained from using the term Ares IV). He suggested that NASA might want to test some Ares V systems and Orion systems by flying the
Ares 1 upper stage atop a Ares V first stage. This would probably result in putting the entire Ares 1 upper stage and into orbit. A series of engine firings would then put the Orion on a
trajectory that would allow it to experience lunar reentry speeds.
New Rockets in Their Back Pockets?
When I asked Horowitz if this Ares IV as part of an alternate architecture to implement the VSE he more or less dismissed the notion. Specifically, the "Ares IV" was not being considered
as a replacement for the human launch capability of the Ares 1. Mike Griffin said the same thing a week or so earlier at a Space Transportation Association breakfast when I asked him the
same question.
Horowitz also downplayed the notion put forth by some that you might use two "Ares IV" vehicles — one for crew, the other for the lunar lander, as an alternate way to get humans to the Moon.
Among other things he said that such an approach would require dramatic changes to the LSAM (lander).
In Summary
Horowitz certainly put forth a positve picture of Ares 1 and Orion developement. Yes, there are weight growth issues. Yes, NASA is tracking them. No, NASA does not feel that its proposed
launch systems will be incapable of doing their job when called upon to do so.
Horowitz said that he now hopes to have regular press updates — perhaps on a monthly basis. This is a smart thing to do — if for no other reason than to try and shoot down rumors
at an early stage and/or admit to problems before arm waving outpaces facts.
