SpaceX Falcon 9 Block 4 - OTV-5 - Launching September 7, 2017
Screenshot of SpaceX Falcon 9 B4 - OTV-5 hosted by Tim Dodd
Mission Rundown: SpaceX Falcon 9 B4 - OTV-5
Written: January 23, 2021
It’s a secret Space Plane. Don’t look
SpaceX’s Falcon 9 rocket will launch the U.S. Air Force’s X-37B Orbital Test Vehicle (OTV) on its fifth mission. This is the 13th launch for SpaceX this year and 41st launch of the Falcon 9 overall. It will launch from pad 39A at Kennedy Space Center in Florida. After stage separation, they will be attempting a first stage landing back at the Cape Canaveral Air Force Base at LZ-1 placed about 6 miles from the launch pad.
The primary launch window opens on Thursday, September 7 at 9:50 a.m. EDT or 13:50 UTC, and closes at 2:55 p.m. EDT or 18:55 UTC.
Boeing X-37
The Orbital Test Vehicle (OTV), is a reusable robotic spacecraft. It is boosted into space by a launch vehicle, then reenters Earth's atmosphere and lands as a spaceplane. The X-37 is operated by the United States Space Force, and was previously operated by Air Force Space Command until 2019 for orbital spaceflight missions intended to demonstrate reusable space technologies.
The X-37 began as a NASA project in 1999, before being transferred to the United States Department of Defense in 2004.
The X-37 first flew during a drop test in 2006; its first orbital mission was launched in April 2010 on an Atlas V rocket, and returned to Earth in December 2010. Subsequent flights gradually extended the mission duration, reaching 780 days in orbit for the fifth mission, the first to launch on a Falcon 9 rocket. The latest mission, the sixth, launched on an Atlas V on 17 May 2020.
The aerodynamic design of the X-37 was derived from the larger Space Shuttle orbiter, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at higher altitudes and Mach numbers compared to DARPA's Hypersonic Technology Vehicle. An early requirement for the spacecraft called for a total mission delta-v of 7,000 miles per hour (3.1 km/s) for orbital maneuvers. An early goal for the program was for the X-37 to rendezvous with satellites and perform repairs.
The X-37 was originally designed to be carried into orbit in the cargo bay of the Space Shuttle, but underwent redesign for launch on a Delta IV or comparable rocket after it was determined that a shuttle flight would be uneconomical.
The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. Thereafter, the program became a classified project. DARPA promoted the X-37 as part of the independent space policy that the United States Department of Defense has pursued since the 1986 Challenger disaster.
An X-37B inside its 5 meter Atlas V 501 payload fairing
The X-37 Orbital Test Vehicle is a reusable robotic spaceplane. It is an approximately 120-percent-scale derivative of the Boeing X-40, measuring over 29 feet (8.8 m) in length, and features two angled tail fins. The X-37 launches atop an Atlas V 501 or a SpaceX Falcon 9 rocket. The spaceplane is designed to operate in a speed range of up to Mach 25 on its re-entry.
The technologies demonstrated in the X-37 include an improved thermal protection system, enhanced avionics, an autonomous guidance system and an advanced airframe. The spaceplane's thermal protection system is built upon previous generations of atmospheric reentry spacecraft, incorporating silica ceramic tiles. The X-37's avionics suite was used by Boeing to develop its CST-100 crewed spacecraft. The development of the X-37 was to "aid in the design and development of NASA's Orbital Space Plane, designed to provide a crew rescue and crew transport capability to and from the International Space Station", according to a NASA fact sheet.
The X-37 for NASA was to be powered by one Aerojet AR2-3 engine using storable propellants, providing thrust of 6,600 pounds-force (29.4 kN). The human-rated AR2-3 engine had been used on the dual-power NF-104A astronaut training vehicle and was given a new flight certification for use on the X-37 with hydrogen peroxide/JP-8 propellants. This was reportedly changed to a hypergolic nitrogen-tetroxide/hydrazine propulsion system.
Also featured in this launch is the Aerojet Rocketdyne's XR-5A Xenon Gas Hall Effect Thruster, which is replacing one of the original Aerojet AR2-3 engines. Compared to chemical engines, the thrust is very small, on the order of 83 mN for a typical thruster operating at 300 V, 1.5 kW.
For comparison, the weight of a coin like the U.S. quarter or a 20-cent Euro coin is approximately 60 mN. As with all forms of electrically powered spacecraft propulsion, thrust is limited by available power, efficiency, and specific impulse.
The X-37 lands automatically upon returning from orbit and is the second reusable spacecraft to have such a capability, after the Soviet Buran shuttle. The X-37 is the smallest and lightest orbital space plane flown to date; it has a launch mass of around 11,000 pounds (5,000 kg) and is approximately one quarter of the size of the Space Shuttle orbiter. - Wikipedia.
