(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Reusable NewSpace: Reentry Vehicle, Part I [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.'] Date: 2024-06-12 “Anyone who sits on top of the largest hydrogen-oxygen fueled system in the world, knowing they’re going to light the bottom, and doesn’t get a little worried, does not fully understand the situation.” – John Young TABLE OF CONTENTS =<<>>= VENTURESTAR ARCHITECTURE We will dust off a decades–old Vertical Takeoff Horizontal Landing (VTHL) Single–Stage–To–Orbit (SSTO) reusable Reentry Vehicle (RV) design called the VentureStar. Image 1: The X-33 was the proof-of-concept vehicle for the VentureStar The VentureStar was supposed to start out as the X–33 proof–of–concept vehicle. The X–33 was a smaller–scale version of the VentureStar (Image 1) and would have flown suborbital flight tests, where it would have launched vertically from one location and landed horizontally in another. All aspects of flight test operations would have been evaluated, from un–crewed drone operations to the Thermal Protection System (TPS) to turnaround times between flights. Once all the bugs had been worked out on the X–33, the VentureStar itself would have then been constructed and flown. The X–33 was a lifting body–design, but later studies showed that it would not have provided sufficient lift capabilities. The wings were enlarged later in the design process which included a lower dihedral angle. There was also a problem with the propellant tanks, which were supposed to use composite material instead of aluminum. Since the technology for Composite Propellant Tanks (CPT) was in its infancy in the late 1990s, it was inevitable that the tanks failed. CPTs are, of course, routinely manufactured nowadays, so our spacecraft propellant tanks will be made from the same material. Work actually began on the X–33 and was almost completed when the funding ax fell. The launch and landing facilities were mostly complete, and the mission control center was essentially operational. They even had a plan to ferry the X–33 on the back of a modified Boeing 747, just like the US Space Shuttle did. The VentureStar RV would have replaced the US Space Shuttle at the dawn of the 21st Century. Alas, the Funding Equation was inadequate and led to its demise. :: We will incorporate modern technology, techniques, and materials to create an updated version of the VentureStar. The original VentureStar was designed to insert 25,400 kg mass to a 200 km altitude with a gross mass of 1,180,000 kg. Our new and improved VentureStar will deposit just under 32,360 kg to the same orbital altitude even though our design will be slightly heavier than the original design at 1,244,577 kg. Equations PROPELLANT MASS = LH 2 MASS + LO 2 MASS MASS + LO MASS EMPTY MASS = STRUCTURAL MASS + ROCKET ENGINE MASS + SUBSYSTEMS MASS PAYLOAD MASS = 32,359 kg to 200 km GROSS MASS = PROPELLANT MASS + EMPTY MASS + PAYLOAD MASS GROSS LIFTOFF WEIGHT = g 0 (GROSS MASS) (GROSS MASS) g 0 = Standard Earth Gravity :: Propellant PROPELLANT MASS = LH 2 Mass + LO 2 Mass = 169262 + 930944 = 1,100,206 kg Empty Mass EMPTY MASS = STRUCTURAL MASS + ROCKET ENGINE MASS + SUBSYSTEMS MASS = 75919 + 28625 + 7467 = 112,012 kg Gross Mass GROSS MASS = PROPELLANT MASS + EMPTY MASS + PAYLOAD MASS = 1100206 + 112012 + 32359 = 1,244,577 kg Gross Liftoff Weight GLOW = g 0 (GROSS MASS) = 9.80665(1244557) = 12,205,130 N =<<>>= VENTURESTAR AIRFRAME The VentureStar has a typical launch vehicle internal structure using CPTs. Similar to the Space Shuttle design, the LO 2 Tank is placed atop the LH 2 Tank. In this case, the LO 2 Tank is lobed and two (not one) LH 2 Tanks are placed underneath and on either side forming the isosceles triangular shape (Image 2). Image 2: VentureStar Interior View The rocket engines are placed underneath the two LH 2 Tanks, forming the base of the triangle. The Cargo Hold is situated between the two LH 2 Tanks. :: The VentureStar looks very similar to the US Space Shuttle, with a white surface on the top and a dark metallic Thermal Protection System (TPS) heat shield on the bottom.. On the ground, the VentureStar would look like any other ordinary spaceliner. =<<>>= VENTURESTAR POWERPLANT The VentureStar utilizes a unique type of rocket engine called the RS–2200. Image 3: The Aerospike nozzle Instead of the using a normal rocket engine design, we will use a linear aerospike engine (Image 3). The rocket uses a clever principle of aerodynamics by using the atmosphere to shape part of the rocket exhaust as it pierces through the atmosphere. The ISP of any rocket is always lower at sea level than in the vacuum of space; the aerospike concept helps to mitigate the loss. The rocket engine specifications are summarized in the Table below. Name RS–200 Type Aerospike Cycle Gas Generator Oxidizer / Fuel Ratio 5.5 :1 Nozzle Area Ratio 58 :1 Isp (Sea Level) 339 s Isp (Vacuum) 439 s Vexh (Sea Level) 3.324 kps Vexh (Vacuum) 4.305 kps Thrust (Sea Level) 1,917,000 N The VentureStar will use a total of seven RS–2200 rocket engines. TOTAL THRUST = 7(RS–2200 THRUST) = 7(1917000) = 13,419,000 N Therefore, the VentureStar Thrust–to–Weight Ratio is: THRUST–TO–WEIGHT RATIO = (TOTAL THRUST / GLOW) : 1 = (13419000 / 1244577) : 1 = 1.09946 : 1 =<<>>= ORBITAL PARAMETERS The minimum altitude needed to orbit the Earth is 200 km. This altitude is temporary since there is a high degree of atmospheric drag causing orbital decay. Orbital altitude is not dependent on the location of the launch site. An orbital altitude of 282 km happens to work out to exactly 16 revolutions around the planet in one 24–hour period of time. A spacecraft would pass over the same geographic location at the same time of day every day ad nauseum. This situation would allow for regularly scheduled spaceflight launches and recovery since the ground tracks repeat. This altitude, however, is not suitable for a large and heavy space station that would constantly need to be re–boosted due to orbital decay. A better altitude is 901 km, which orbits the Earth exactly 14 times per day. This altitude provides for an extremely stable orbit essentially free of decay and will be perfect for a large and heavy space station without the inconvenience of repetitive re–boost. More importantly, this situation would allow for regularly scheduled spaceflight launches and recovery since the ground tracks repeat. Launches would occur at the same time of day every day. The Table below summarizes the required orbital parameters of the VentureStar RRV launching from Spaceport America and flying into Standard Orbit. Orbital Altitude 600.96 km Orbits 14 /day Orbital Period 6,171 s 102.9 min 1.714 hrs Inclination 60o =<<>>= [END] --- [1] Url: https://www.dailykos.com/stories/2024/6/12/2243305/-Reusable-NewSpace-Reentry-Vehicle-Part-I?pm_campaign=front_page&pm_source=more_community&pm_medium=web Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/