“In the summer of 2016, Copenhagen Suborbitals launched one of the most advanced liquid fueled rockets built by a team of volunteer amateurs. Follow the team close up during final preparations for the launch and during the launch of the Nexø I rocket. Enjoy.
Copenhagen Suborbitals is the world’s only manned, amateur space program, 100% crowdfunded and nonprofit. In the future, one of us will fly to space on a home built rocket.”
“Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton’s laws of motion and Newton’s law of universal gravitation. It is a core discipline within space mission design and control. Celestial mechanics treats more broadly the orbital dynamics of systems under the influence of gravity, including both spacecraft and natural astronomical bodies such as star systems, planets, moons and comets. Orbital mechanics focuses on spacecraft trajectories, including orbital maneuvers, orbit plane changes, and interplanetary transfers, and is used by mission planners to predict the results of propulsive maneuvers.
In orbital mechanics, the Hohmann transfer orbit is an elliptical orbit used to transfer between two circular orbits of different radii in the same plane. The orbital maneuver to perform the Hohmann transfer uses two engine impulses, one to move a spacecraft onto the transfer orbit and a second to move off it.
A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a Hohmann transfer orbit used to reach geosynchronous or geostationary orbit using high thrust chemical engines. Geosynchronous orbits (GSO) are useful for various civilian and military purposes, but demand a great deal of Delta-v to attain. Since, for station-keeping, satellites intended for this orbit typically carry highly efficient but low thrust engines, total mass delivered to GSO is generally maximized if the launch vehicle provides only the Delta-v required to be at high thrust–i.e., to escape Earth’s atmosphere and overcome gravitational losses–and the satellite provides the Delta-v required to turn the resulting intermediate orbit, which is the GTO, into the useful GSO.
GTO is a highly elliptical Earth orbit with an apogee of 42,164 km (26,199 mi), or 35,786 km (22,236 mi) above sea level, which corresponds to the geostationary altitude. The period of a standard geosynchronous transfer orbit is about 10.5 hours. The argument of perigee is such that apogee occurs on or near the equator. Perigee can be anywhere above the atmosphere, but is usually restricted to a few hundred kilometers above the Earth’s surface to reduce launcher delta-V requirements and to limit the orbital lifetime of the spent booster so as to curtail space junk. If using low-thrust engines such as electrical propulsion to get from the transfer orbit to geostationary orbit, the transfer orbit can be supersynchronous (having an apogee above the final geosynchronous orbit). This method however takes much longer to achieve due to the low thrust injected into the orbit. The typical launch vehicle injects the satellite to a supersynchronous orbit having the apogee above 42,164 km. The satellite’s low thrust engines are thrusted continuously around the geostationary transfer orbits in an inertial direction. This inertial direction is set to be in the velocity vector at apogee but with an outer plane direction. The outer plane direction removes the initial inclination set by the initial transfer orbit while the inner plane direction raises simultaneously the perigee and lowers the apogee of the intermediate geostationary transfer orbit. In case of using the Hohmann transfer orbit, only a few days are required to reach the geosynchronous orbit. By using low thrust engines or electrical propulsion, months are required until the satellite reaches its final orbit.
The inclination of a GTO is the angle between the orbit plane and the Earth’s equatorial plane. It is determined by the latitude of the launch site and the launch azimuth (direction). The inclination and eccentricity must both be reduced to zero to obtain a geostationary orbit. If only the eccentricity of the orbit is reduced to zero, the result may be a geosynchronous orbit but will not be geostationary. Because the Delta V required for a plane change is proportional to the instantaneous velocity, the inclination and eccentricity are usually changed together in a single manoeuvre at apogee where velocity is lowest.”
“CisLunar – the space between Earth and the moon – holds vast opportunities for humans. Reliable, accessible, affordable access to space will help open economic opportunities. ULA’s ability to provide reliable, affordable access to space, which will provide critical infrastructure to supporting a space economy.”
“Originally proposed as the Advanced Cryogenic Evolved Stage by Boeing in 2006 as a concept for use as a new Delta IV second stage — and subsequently, the Advanced Common Evolved Stage by its corporate successor, United Launch Alliance by 2010 — ACES was intended to boost satellite payloads to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity. Other alternative uses included a proposal to provide in-space propellant depots in LEO or at L2 that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or interplanetary missions, and to provide the high-energy technical capacity for the cleanup of space debris.
The late-2000s ACES proposal by ULA also had a predecessor at Lockheed Martin, prior to the merger of Boeing and Lockheed Martin launch vehicle manufacturing and operations to form ULA in 2006. Known then as the Lockheed Martin common-stage concept, the upper stage was intended to “provide efficient, robust in-space transportation”, and take advantage of the high-mass fraction that is enabled by Centaur’s design and its common bulkhead to minimize combined LO2/LH2 boil off. A study funded by NASA led to the development of the Lockheed Martin concept known as ACES, under the original name of Advanced Cryogenic Evolved Stage as of 2006.
In April 2015, after ULA had announced the end of production of the Delta IV Medium in 2019 and the Delta IV Heavy in the mid-2020s, ULA renamed the stage the Advanced Cryogenic Evolved Stage, as ACES would in this case serve as the second stage on only a single launch vehicle, the Vulcan, beginning no earlier than 2023.
After the formation of ULA in 2006, the ACES concept became one that would provide a common stage that would be evolved from both Atlas and Delta rocket technology and could be used on both launch vehicles — thus “common”. The concept by 2010 was to utilize the new high-performance upper stage, if built, on both Atlas V and Delta IV/Delta IV Heavy launch vehicles. As further refined in a 2010 conference paper, ACES was intended to be a lower-cost, more-capable and more-flexible upper stage that would supplement, and perhaps replace, the existing ULA Centaur and Delta Cryogenic Second Stage (DCSS) upper stage vehicles.
In April 2015, ULA renamed the stage the Advanced Cryogenic Evolved Stage, and announced conceptual plans to complete development of the ACES technology for the Vulcan launch vehicle, flying no earlier than 2023, but currently planned for 2024-25. No plans to develop the stage for the Atlas V or Delta IV launch vehicle lines remain. However, just like earlier ACES concept proposals, ACES would continue to blend technical aspects of both Delta and Atlas technologies and manufacturing processes, as well as use ULA’s proprietary Integrated Vehicle Fluids (IVF) technology to significantly extend the ability of the upper stage to operate in space long term. The IVF technology utilizes a lightweight internal combustion engine to use propellant boiloff (normally wasted when boiloff gasses are vented to space) to operate the stage including production of power, maintaining stage attitude, and keeping the propellant tanks autogenously pressurized, eliminating the need for hydrazine fuel and liquid helium.
The ACES vehicle is “based on a simple modular design” where the “use of multiple barrel panels, similar to Centaur, provides a straightforward means to building multiple-length (propellant load) stages that are otherwise common. The common equipment shelf accommodates one, two, or four RL10 engines. While ACES can start with existing Centaur and Delta pneumatic, avionics and propulsion systems it is intended to transition to lower-cost and higher capability systems founded on the Integrated Vehicle Fluids (IVF) system concept. IVF eliminates all hydrazine, helium, and nearly all batteries from the vehicle. It consumes waste hydrogen and oxygen to produce power, generate settling and attitude control thrust, and autogenously pressurize the vehicle tanks. IVF is optimal for depot operations since only LH2 and LO2 need be transferred, and it extends mission lifetimes from the present dozen hours to multiple days.” With the addition of a solar power system, the vehicle can remain in space and operate indefinitely.”
“On October 15, 1997, a seven-year journey to the ringed planet Saturn began with the liftoff of a Titan IVB/Centaur carrying the Cassini orbiter and its attached Huygens probe. This spectacular streak shot was taken from Hangar AF on Cape Canaveral Air Force Station, with a solid rocket booster retrieval ship in the foreground. Launch occurred at 4:43 a.m. EDT from Launch Complex 40. After a nearly 2.2-billion mile journey, the spacecraft arrived in the Saturn system on June 30, 2004.”
“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.
No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.
On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.
Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. (And those six months are the thrilling final chapter in a historic 20-year journey.)”
“NASA’s Cassini spacecraft arrived at Kennedy Space Center 20 years ago to begin processing for launch on a mission that would see it deliver spectacular images and data from the ringed planet Saturn. As the massive spacecraft begins its final chapter, engineers at Kennedy took a look back to how their contributions to the mission began.”
“On April 22, hours arriving at the International Space Station, Orbital ATK’s Cygnus resupply ship was captured by Expedition 51 Flight Engineer Thomas Pesquet of the European Space Agency and Commander Peggy Whitson of NASA using the Canadarm2 robotic arm. Later, Cygnus was installed to the Earth-facing port of the Unity module where it will reside for the next three months. Cygnus is packed with 7,600 pounds of supplies and research for the crew aboard the orbiting laboratory.”
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