View source for Shuttle-Derived Heavy Lift Launch Vehicle

{{Short description|Space launch vehicle concept}}{{About|a side-mount concept|other concepts of Shuttle-Derived Heavy Lift Launch Vehicles|Shuttle-derived vehicle}}
[[File:Nasansc.JPG|thumb|right|upright=1.4|Artist impression of the Shuttle-Derived HLV concept]]
The '''Shuttle-Derived Heavy Lift Launch Vehicle''' ("'''HLV'''") was an alternate [[super heavy-lift launch vehicle]] proposal for the [[NASA]] [[Constellation program]]. It was first presented to the [[Review of United States Human Space Flight Plans Committee|Augustine Commission]] on 17 June 2009.
Based on the [[Shuttle-C]] concept which has been the subject of various studies since the 1980s, the HLV was a [[Shuttle-derived vehicle|Shuttle-Derived Launch Vehicle]] (SDLV) that proposed to replace the winged Orbiter from the Space Shuttle stack with a side-mounted payload carrier. The Space Shuttle's External Tank (ET) and four-segment Shuttle Solid Rocket Boosters (SRBs) would have remained the same.
According to initial estimates, the HLV could have been developed within 4{{frac|1|2}} years for about US$6.6 billion,<ref name="AP">{{cite news|first=Seth |last=Borenstein |title=NASA manager pitches a cheaper return-to-moon plan |publisher=[[Associated Press]] |date= June 30, 2009}}</ref> which was about 20% of the costs estimated for the [[Ares I]] and [[Ares V]] vehicle development.
== Origin ==
[[File:Shuttle-c launch painting.jpg|thumb|right|upright=1.1|An artist's conception of a Shuttle-C launching at night]]
An uncrewed side-mounted concept of the Space Shuttle named Shuttle-C was investigated between 1984 and 1995.<ref name="globalsec">{{cite web |url= http://www.globalsecurity.org/space/systems/sts-c.htm |title = Shuttle-C |publisher = GlobalSecurity.org |access-date = 2009-01-20}}</ref> The Shuttle-C cargo only option was not funded in the 1980s and 1990s due to NASA's budgetary constraints. After the [[Space Shuttle Columbia disaster|Space Shuttle ''Columbia'' disaster]], a two-year industry study was prepared in 2004 and 2005 to further investigate the concept as a Shuttle replacement. The [[Exploration Systems Architecture Study]] (ESAS) in 2005 also investigated a Shuttle-C option for Project Constellation, again only in an uncrewed version. All these concepts intended the side-mounted carrier to be an autonomous spacecraft which would detach from the External Tank after main engine cut-off, similarly to the Space Shuttle. Some of the studies included the reuse of the Space Shuttle Main Engines on this side-mounted carrier. None of the concepts involved in-ascent fairing separation.{{citation_needed|date=July 2019}}
The HLV proposal presented on 17 June 2009 was partly based on the original [[Shuttle-C]] proposal. The main differences were that the side-mounted carrier could not detach from the ET, and proposing to also carry crews on the HLV. The proposal included work from about 60 NASA engineers.<ref>{{cite web |date= July 6, 2009 |author=Keith Cowing |url=https://nasawatch.com/shuttle-news/more-internal-validation-of-sidemount-hlv/ |title=More Internal Validation of Sidemount HLV |publisher=NASA Watch |access-date=April 1, 2023}}</ref>
== HLV specifications ==
[[File:High Confidence Heavy Lift Launch Vehicle Diagram.jpg|thumb|upright=1.6|A diagram of the Shuttle-Derived Heavy Lift Launch Vehicle, Block I configuration]]
The HLV was proposed to be a {{convert|4600000|lb|kg}} vehicle at liftoff with two 4-segment [[Space Shuttle Solid Rocket Booster]]s weighing about {{convert|2600000|lb|kg}} providing a total thrust of {{convert|5900000|lbf|MN}} at sea level and the [[Space Shuttle External Tank]] weighing about {{convert|1660000|lb|kg}} fueled.
The side-mounted carrier was to include a Shuttle-derived 'boattail' carrying the three [[Space Shuttle Main Engine]]s and other propulsion elements. A {{convert|7.5|m|ft|sp=us}} diameter payload carrier with a separable fairing weighing {{convert|51000|lb|kg}} would take up the space usually occupied by the rest of the orbiter. The basic vehicle would not have an upper stage, requiring the payload to perform orbit circularization and possibly [[trans-lunar injection]] burns.<ref name="autogenerated1">{{cite web |title=Shuttle-Derived Heavy Lift Launch Vehicle |date= June 17, 2009 |url= http://www.nasa.gov/pdf/361842main_15%20-%20Augustine%20Sidemount%20Final.pdf |work= [[Review of United States Human Space Flight Plans Committee]] |publisher= NASA}}</ref>
The only completely new hardware development to be required for the HLV was the side-mounted carrier. All other components used on the HLV were previously in use with the Space Shuttle, and up to the first six flights of the vehicle would have reused spare parts and salvaged functioning hardware from the orbiters, including existing [[avionics]] modules, flight software, and SSMEs (Block I flights). Virtually no change to the existing Space Shuttle infrastructure, from the [[Vehicle Assembly Building]] to the External Tank barge to the launch pads, was to be required.{{citation_needed|date=July 2019}}
===Upper stage===
To be usable for the envisioned lunar flights, the HLV would require an upper stage. The use of the [[J-2X]] engine that was under development for the [[Ares I]] launch vehicle was proposed for this upper stage. It would have provided nearly {{convert|300000|lbf|MN}} (vacuum) and was intended to have a specific impulse (Isp) of 448 sec.{{citation_needed|date=July 2019}}
Alternatively, the United Launch Alliance (ULA) proposed that their Dual Thrust Axis Lander (DTAL) could fit in a side mount payload shroud. The ULA ACE 41 and ACE 71 upper stage/fuel depot concepts could have also fitted inside a side mount payload shroud, and the ACE 71 at {{convert|75|MT|ST}} was well within the side mount shuttle derived vehicle's payload capacity.<ref>{{cite web |url=http://www.ulalaunch.com/docs/publications/AffordableExplorationArchitecture2009.pdf |title=A Commercially Based Lunar Architecture |access-date=2009-09-12 |url-status=dead |archive-url=https://web.archive.org/web/20091104134500/http://www.ulalaunch.com/docs/publications/AffordableExplorationArchitecture2009.pdf |archive-date=2009-11-04 }}. ULA</ref>
===Performance===
The HLV's 4-segment SRBs were to deliver a specific impulse (Isp) of 267 sec and a thrust of {{convert|5900000|lbf|MN}} and burn for about 155 seconds. The SSME main engines were to be flown at 104.5% and deliver a specific impulse (Isp) of 452 sec and {{convert|1500000|lbf|MN}} (vacuum) and burn for about 500 seconds (depending on the mission profile). The payload mass for different missions was envisioned as follows:<ref name="flightglobal1">{{cite web|url=http://www.flightglobal.com/articles/2009/06/29/328988/will-son-of-shuttle-c-replace-nasas-ares.html |title=Will son of Shuttle-C replace NASA's Ares? |publisher=Flightglobal.com |date=2009-06-29 |access-date=2009-07-18}}</ref>
*Block I vehicle without an upper stage – {{convert|79|MT|lb}} (gross) and {{convert|71|MT|lb}} (net) to a {{convert|120|nmi|km}} × {{convert|120|nmi|km}} reference orbit (28.5°) from [[Kennedy Space Center]]
*Block II cargo vehicle with an upper stage (mass of upper stage not included) – {{convert|90|MT|lb}} (gross) and {{convert|81|MT|lb}} (net) to a {{convert|120|nmi|km}} × {{convert|120|nmi|km}} reference orbit (28.5°) from Kennedy Space Center
*Block II crew vehicle with an upper stage (mass of upper stage not included) – {{convert|92|MT|lb}} (gross) and {{convert|83|MT|lb}} (net) to a {{convert|120|nmi|km}} × {{convert|120|nmi|km}} reference orbit (28.5°) from Kennedy Space Center
*Block II lunar missions: {{convert|39|MT|lb}} to TLI (gross) with the lunar lander and {{convert|35|MT|lb}} to TLI (net)<ref name="autogenerated1"/> from Kennedy Space Center.
===Mission profile===
In contrast to [[Shuttle-C]], no part of the vehicle (except for the 4-segment SRBs) would have been recoverable and reusable. The HLV could have used a different flight profile than Shuttle because of a lack of wings and associated load limits. The payload fairing {{convert|23000|lb|kg}} was to be jettisoned 185 seconds into the flight at about {{convert|57|nmi|km}} altitude. The SSME main engines were not to be reused and thus could be simplified, and new engines would have to be produced for each vehicle. For lunar missions, the HLV proposal envisioned suborbital staging at {{convert|30|nmi|km}} × {{convert|120|nmi|km}} of the vehicle to increase mass through TLI (trans-lunar injection) with two burns of the upper stage (a suborbital burn and an additional TLI burn).{{citation_needed|date=July 2019}}
==Lunar mission architecture==
[[image:Shuttleclunar.svg|thumb|right|400px|Lunar mission scenario with the HLV, a lunar lander and the Orion spacecraft]]
While the HLV was designed to provide crew and cargo missions to the ISS, its primary aim would have been to replace the Ares I – Ares V lunar architecture. The rudimentary mission architecture used a [[Lunar Orbit Rendezvous]] profile. Two HLVs were to be launched for the completion of one mission. The first HLV was to be launched with the [[Altair (spacecraft)|lunar lander]] and immediately place the lunar lander on a trans-lunar injection. The lunar lander would have had a net mass of 35 metric tons after TLI, and would have inserted itself into a low lunar orbit (LLO). In LLO, the lunar lander would weigh about 28 metric tons.<ref name="flightglobal1"/>
The second HLV was to place an [[Orion spacecraft]] and crew to trans-lunar injection. The 20 metric ton Orion spacecraft would remain attached to the upper stage, which was to insert the Orion spacecraft into LLO and dock with the lunar lander.{{Citation_needed|date=July 2019}}
==Growth options==
The HLV would have had limited growth option. While 5-segment SRBs could have been used on the vehicle, they would have required significant re-engineering to yield 7 metric tons more to lower Earth orbit. Other growth options included an upgrade of the SSME to 106% or 109% thrust level or a switch from the J-2X upper engine to an air-startable SSME.<ref name="autogenerated1"/>
== See also ==
* [[Jupiter (rocket family)]]
* [[Magnum (rocket)]], a 1990s Shuttle-derived heavy lift vehicle concept.
* [[Review of United States Human Space Flight Plans Committee]]
==References==
{{reflist}}
== External links ==
*[http://www.nasawatch.com/images/heft2.pdf HEFT about Heavy Lift Launch Vehicle]
*[https://www.youtube.com/watch?v=xOnlAUpYWoc YouTube: NASA Shuttle-derived Sidemount Heavy Launch Vehicle Concept] (First Shown on June 17, 2009)
*[http://www.universetoday.com/2009/07/01/faster-cheaper-and-better-way-to-the-moon/ Universe Today: Faster, Cheaper (and Better?) Way to the Moon] (July 1, 2009)
*[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/07/05/MN2218GD18.DTL&type=science ''San Francisco Chronicle': Backup plan to get NASA to moon cheaper] (July 5, 2009)
* [https://web.archive.org/web/20100331235522/http://www.ulalaunch.com/docs/publications/DualThrustAxisLander(DTAL)2009.pdf United Launch Alliance Lunar lander paper]
*[https://www.youtube.com/watch?v=Il4xDpx4rJk YouTube: NASA's Shuttle-Derived Heavy Lift Launch Vehicle Concept] animation by YouTube user Hazegrayart
{{Rocket families}}
{{Space Shuttle}}
{{Project Constellation}}
[[Category:Partially reusable space launch vehicles]]
[[Category:Shuttle-derived space launch vehicles]]
[[Category:Constellation program]]
[[Category:NASA space launch vehicles]]