FREQUENTLY ASKED QUESTIONS
Below we are collecting a series of common questions regarding the DIRECT Concept:
Question: What is the difference between NLS, DIRECT v1.0, DIRECT v2.0, and DIRECT v3.0?
Answer: In the early 1990’s, NASA’s Marshall Space Flight Center (MSFC) designed a heavy lift launch vehicle to complement the Space Shuttle in constructing a space station. This vehicle, known as the National Launch System or NLS, successfully passed its Preliminary Design Review (PDR), which several Constellation components have yet to pass. However, the program went unfunded during the Clinton administration and the NLS was relegated to the filing cabinets.
In 2006, Ross Tierney revitalized and updated NLS on NASASpaceflight.com as an alternative to the Ares launch vehicles, which were facing development problems. At the same time, TeamVision corporation concluded a similar study with a vehicle nearly identical to Tierney’s DIRECT. The proposals merged to create DIRECT v1.0, advocating a single launch vehicle to fulfill both the Crew and Cargo launch roles. In late 2006, Dr. Doug Stanley of MSFC criticized DIRECT’s use of a highly evolved version of the Delta IV’s RS-68 engine on DIRECT’s first stage. Labeling the concept as unworkable, he maintained that Ares was the only way forward.
In 2007, the DIRECT team came forward at the ISDC conference with a new variant of the DIRECT launch vehicle, this time known as Jupiter. It was powered by standard RS-68 engines and the same J2-X that NASA was using for it’s Ares upper stages. NASA offered another performance critique of the system, claiming that it did not achieve stated performance. DIRECT’s v2.0 Rebuttal Document explains why NASA used several flawed starting assumptions to come to a flawed result.
At the same time, DIRECT had identified the thermal environment on both Ares V and DIRECT’s core stage to be too extreme for the standard RS-68 engine to handle. This mandated a switch to the SSME as the core stage engine for DIRECT, which also began to recommend that the existing RL-10 be used as the upper stage engine in lieu of the J2-X. This became known as DIRECT 3.0, which was presented publicly in May 2009.
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Question: Is there a ‘white paper’ on DIRECT v3.0?
Answer: A Summary Document similar to the one for DIRECT v2.0 is forthcoming, but the priority is on working with the Augustine Commission. You can view our latest presentation on the homepage.
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Question: How does the naming convention work?
Answer: All vehicles are known as Jupiter/# of stages/# of first stage engines/# of second stage engines. Thus, Jupiter-130 has 1 stage with 3 SSME’s on it. Jupiter-246 has 2 stages with 4 SSME’s on the first stage and 6 RL-10’s on the second stage. ‘H’ is appended on the end of the configuration uses 5-segment SRB’s. DIRECT does not recommend nor require using them, but retains the capability to do so.
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Question: Why are there so many configurations in the Technical Data Summary Section?
Answer: DIRECT is an incredibly flexible launch vehicle. We don’t want to lock into just one or two configurations; we want to present all of the options and allow NASA to choose the best for their needs. In reality, only one or two would ever be flown. We have also presented the options flying to a variety of orbits and payload configurations.
We recommend the Jupiter-130 powered by SSME’s and the Jupiter-246 using RL-10-B2’s.
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Question: What is the maximum performance for the different variants of DIRECT?
Answer: The performance figures are continually under review. Please see the ‘Media’ section to view performance summaries for all of the DIRECT configurations.Back To Top
Question: Isn't the 70+ mT CLV performance a little excessive for ISS Crew Launch flights?
Answer: No. It is always better to have spare performance capacity than to have too little -- which is one of the critical concerns with the Ares-I.
Both Jupiter launchers have more than sufficient performance to lift the 22mT Orion CEV. But, having the ability to also bring up a further 40-50mT of additional payload gives NASA the option to launch a cargo module to space the same way that Shuttle can with every crew. This is an ability the US will lose after Shuttle retires in 2010 because the Ares-I is unable to lift any additional payload at all.
This extra performance is primarily intended for use by the Lunar missions, where the Crew Launch will lift the Altair Lunar Surface Access Module (LSAM) as well as the Orion spacecraft. A two-launch strategy using this technique is capable of sending almost 80 metric tons of payload towards the moon on every manned mission.
For ISS flights, the Crew Launch can bring up large quantities of spares, supplies and scientific equipment, all for no extra cost and can do so [b]without compromising the safety of the crew[/b]. It could even bring up sections of the ISS which have been cancelled due to the Shuttle's early retirement, such as:
If no additional payload needs to be lifted with an Orion CEV spacecraft, the additional capacity could be utilized to fly a ballistic shield under the spacecraft as an extra layer of safety between the launcher and the crew. Should the worst happen, a 20 ton water tank would absorb a lot of the debris and shockwaves of any catastrophic failure and add to the safety margin of a crew module trying to escape off the top of the booster. Such a water tank shield is demonstrated in our Video of the DIRECT launch.
Further, there is simply no way Ares-I could perform any future servicing missions to the Hubble Space Telescope without launching a "mission module" on a separate launcher first. The Jupiter 120 does have the lift capacity to launch the very heavy cameras and sensor packages which would be required to keep the telescope operating for a long time to come.
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Question: Why do we claim "Safer, Simpler, Sooner" for the DIRECT Architecture?
For launching crews, Jupiter-130 is safer than Ares-I. According to NASA's standard "Loss of Crew" (LOC) analysis dated 8th November 2007, Jupiter offered a 16.6% improvement over Ares-I's safety rating. NASA specified in the ESAS Report that anything above 1 loss in 1000 flight would be acceptable for LOC, and DIRECT has exceed that requirement by more than 45%.
But that is not the end of the story. There are other factors which are much harder to quantify. Because Jupiter's all have significantly extra launch performance, this allows CEV's to fly with extra safety systems otherwise impossible to fly on Ares-I. Safety systems such as a hardened ballistic shield (weighing tons) can be mounted under the Orion spacecraft. Acting like a bullet-proof vest, this would offer significant additional protection to any crew attempting to escape from the launcher in the event of any catastrophic accident during launch.
Further, the launch is only a small part of the overall safety of any mission. With Jupiter's additional lift performance yet more safety system can be included which massively improve safety during the rest of the missions NASA is planning - systems such as radiation shielding for the Crew Module and significant micro-meteoroid protection and more redundant/backup systems can be included on the CEV. Ares-I though, is incapable of lifting the extra weight of any of these systems. Jupiter wins hands-down for mission safety.
Having said that, "safety" also applies to program risk reduction too. Being a single LV, Jupiter is a whole lot "safer" in economic terms and in cancellation terms than Ares-I & Ares-V together. By requiring only the External Tank and the Jupiter Upper Stage to be built, DIRECT reduces development work to improve schedule confidence.
And "safety" can also be applied to workforce retention and politically sensitive spending around the nation. Because of it's much closer relationship to the existing STS systems, and because the "gap" is reduced by two years, Jupiter helps to guarantee to preserve the STS workforce far more effectively than Ares-I will, given that Ares-V will not follow for almost 10 years after STS is retired.
Is it simpler to build two new launch vehicles instead of one?
Is it simpler to build an all-new 5-segment SRB and then an all new 5.5-segment SRB instead of retaining the 4-segment SRB's which have a 100% successful flight history of more than190 flights under their belts since they were re-designed following Challenger?
Is it simpler to re-design, re-develop and re-qualify the Apollo J-2S engine, while increasing its power by 26% to get the needed performance for Ares-I's J-2X engine, or simpler to use the off-the-shelf RL-10?
Is it simpler to require new versions of the RS-68 which must be improved to have more performance and internal stress capability or to just use the already-flying SSME?
Is it simpler to require an all-new SRB-based First Stage and a cryogenic-based Upper Stage for Ares-I or just modify the external tank for Jupiter-130?
Is it then simpler to require two more cryogenic stages (Core and EDS) for Ares-V or just build the EDS and use it on the same vehicle you have already built?
A first manned Orion CEV flight in September 2012 is two years sooner than the current March 2016 plans.
A first manned Lunar Return mission in June 2017 is also two years sooner than the current 2020+ plans.
Possibly even more importantly, having Heavy Lift launch capability to lift 60-70mT cargo's to orbit in 2012 is a massive improvement over NASA's risky plans today hoping to build the next real Heavy Lift vehicle (Ares-V) seven years later - in 2019.
DIRECT: Safer, Simpler, Sooner.
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Question: How much does DIRECT cost?
Answer: The initial Jupiter-130 will cost about $8.3 billion to develop and the Jupiter Upper Stage required for the Jupiter-246 configuration will cost another $2.5 billion.
Per flight, the Jupiter-130 will cost about 160 million and the Jupiter-246 about 240 million.
In comparison, Ares I will cost around $14.4 billion and Ares V upwards of $20 billion.
Per flight, Ares I will cost $130 million and Ares V upwards of $500 million.
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Question: What do the people behind DIRECT personally expect to get out of this?
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We don't want anything for ourselves - not even recognition. The work is not ours, we just can't be fired by NASA for speaking out against the current plans. Most of the contributors to this project don't want to be fired for speaking out, so they wish to remain anonymous. Their primary goal is a more robust US space program than currently being planned. They want something which will provide a better return for the massive investment.
Most people don't believe that we are totally benevolent though, so if there has to be a "price"; we certainly don't think anyone involved would turn down VIP tickets to go watch the first manned launch of a Jupiter launch vehicle. So we will set 70 such tickets as a "fair price" for the work we have done to put this proposal together. Any takers?