“NASA scientists and engineers named their new CubeSat after the mythological Norse god of the dawn. Now, just days from launch, they are confident the shoebox-sized satellite Dellingr will live up to its name and inaugurate a new era for scientists wanting to use small, highly reliable satellites to carry out important, and in some cases, never-before-tried science. Dellingr will study how the ionosphere, a region in Earth’s upper atmosphere, interacts with the Sun. Before launch, Dellingr is required to visit to the Magnetic Test Facility at NASA Goddard to test the spacecraft’s magnetometers – key instruments for measuring the direction and strength of the magnetic fields that surround Earth. The spacecraft is scheduled to launch this August aboard a SpaceX Falcon 9 rocket to the International Space Station where it will be deployed later into a low-Earth orbit.
Music credit: ‘Cycle of Life’ by Philippe Lhommet [SACEM] from Killer Tracks”
Video credit: NASA’s Goddard Space Flight Center/Joy Ng
“The BFR, which is variously said to stand for either Big Falcon Rocket or Big F@#$%^& Rocket, announced in September 2017, is SpaceX’s privately-funded launch vehicle, spacecraft and space and ground infrastructure system of spaceflight technology—including reusable launch vehicles and spacecraft. The system includes Earth infrastructure for rapid launch and relaunch; low Earth orbit, and zero-gravity propellant transfer technology. The new vehicle, while much smaller than an earlier version of SpaceX composite material vehicle design, is much larger than the existing SpaceX operational vehicles which it is intended to replace.
The new launch vehicle is planned to replace both Falcon 9 and Falcon Heavy launch vehicles and the Dragon spacecraft, in the operational SpaceX fleet in the early 2020s, initially aiming at the Earth-orbit market, but explicitly adding substantial capability to the spacecraft vehicles to support long-duration spaceflight in the cislunar and Mars mission environment as well. SpaceX intends this approach to bring significant cost savings which will help the company justify the development expense of designing and building the new launch vehicle design. BFR is a 9 meters (30 ft)-diameter launch vehicle.
An earlier larger design for the first non-Falcon launch vehicle from SpaceX was known as the ITS launch vehicle in 2016–2017. The design for all of the ITS vehicles were 12 meters (39 ft) diameter. While the earlier SpaceX designs had been aimed at Mars transit and other interplanetary uses, SpaceX pivoted in 2017 to a plan that would replace all SpaceX launch-service-provider capacity—Earth orbit, the Lunar-orbit region, and interplanetary space transport—with a single 9 m (30 ft)-diameter class of launch vehicles and spacecraft.
Development work began on the Raptor rocket engines to be used for both stages of the BFR launch vehicle in 2012, and engine testing began in 2016. New rocket engine designs are typically considered one of the longest of the development subprocesses for new launch vehicles and spacecraft. Tooling for the main tanks has been ordered and a facility to build the vehicles is under construction; construction will start on the first ship in 2Q2018. The company publicly stated an aspirational goal for initial Mars-bound cargo flights of BFR launching as early as 2022, followed by the first BFR flight with passengers one synodic period later, in 2024.”
“On August 30, engineers at our Stennis Space Center wrapped up a summer of hot fire testing for flight controllers on RS-25 engines that will help power the new Space Launch System rocket being built to carry astronauts to deep-space destinations, including Mars. The 500-second hot fire of a flight controller or “brain†of the engine marked another step toward the nation’s return to human deep-space exploration missions. Four RS-25 engines, equipped with flight-worthy controllers will help power the first integrated flight of our Space Launch System rocket with our Orion spacecraft, known as Exploration Mission One.”
“The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. On July 23, 1972 the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat. The most recent, Landsat 8, was launched on February 11, 2013. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the U.S. Geological Survey (USGS) ‘EarthExplorer’ website. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 meters; the temporal resolution is 16 days. Landsat images are usually divided into scenes for easy downloading. Each Landsat scene is about 115 miles long and 115 miles wide (or 100 nautical miles long and 100 nautical miles wide, or 185 kilometers long and 185 kilometers wide).
[…] Landsat missions 1 through 5 carried the Landsat Multispectral Scanner (MSS), while missions 4 and 5 used the Landsat Thematic Mapper (TM) scanner. The Multispectral Scanner had a 230 mm (9 in) fused silica dinner-plate mirror epoxy bonded to three invar tangent bars mounted to base of a Ni/Au brazed Invar frame in a Serrurier truss that was arranged with four “Hobbs-Links” (conceived by Dr. Gregg Hobbs), crossing at mid-truss. This construct ensured the secondary mirror would simply oscillate about the primary optic axis to maintain focus despite vibration inherent from the 360 mm (14 in) beryllium scan mirror. This engineering solution allowed the United States to develop LANDSAT at least five years ahead of the French SPOT, which first used CCD arrays to stare without need for a scanner. However, LANDSAT data prices climbed from $250 per computer compatible data tape and $10 for black-and-white print to $4,400 for data tape and $2,700 for black-and-white print by 1984, making SPOT data a much more affordable option for satellite imaging data. This was a direct result of the commercialization efforts begun under the Carter administration, though finally completed under the Reagan administration.
The MSS FPA, or Focal Plane Array consisted of 24 square optical fibers extruded down to 0.005 mm (0.0002 in) square fiber tips in a 4×6 array to be scanned across the Nimbus spacecraft path in a ±6 degree scan as the satellite was in a 1.5 hour polar orbit, hence it was launched from Vandenberg Air Force Base. The fiber optic bundle was embedded in a fiber optic plate to be terminated at a relay optic device that transmitted fiber end signal on into six photodiodes and 18 photomultiplier tubes that were arrayed across a 7.6 mm (0.30 in) thick aluminum tool plate, with sensor weight balanced vs the 230 mm telescope on opposite side. This main plate was assembled on a frame, then attached to the silver-loaded magnesium housing with helicoil fasteners.
Key to the success of the multi spectral scanner was the scan monitor mounted on the underbelly of the magnesium housing. It consisted of a diode light source and a sensor mounted at the ends of four flat mirrors that were tilted so that it took 14 bounces for a beam to reflect the length of the three mirrors from source to sender. The beam struck the beryllium scan mirror seven times as it reflected seven times off the flat mirrors. The beam only sensed three positions, being both ends of scan and the mid scan, but by interpolating between these positions that was all that was required to determine where the multi spectral scanner was pointed. Using the scan monitor information the scanning data could be calibrated to display correctly on a map.”
“Parker Solar Probe is a planned NASA robotic spacecraft to probe the outer corona of the Sun. It will approach to within 8.5 solar radii (5.9 million kilometers or 3.67 million miles) to the ‘surface’ (photosphere) of the Sun. The project was announced as a new mission start in the fiscal 2009 budget year. On May 1, 2008 Johns Hopkins University Applied Physics Laboratory announced it will design and build the spacecraft, on a schedule to launch it in 2015. The launch date has since been pushed back to 2018, with the Delta IV Heavy as the launch vehicle. On May 31, 2017 the probe was renamed after solar astrophysicist Eugene Parker. According to NASA, this was the first time in history a space vessel was named after a living person.
The Parker Solar Probe mission design uses repeated gravity assists at Venus to incrementally decrease the orbital perihelion to achieve multiple passes of the Sun at approximately 8.5 solar radii, or about 6 million km (3.7 million mi; 0.040 AU). The mission is designed to survive the harsh environment near the Sun, where the incident solar intensity is approximately 520 times the intensity at Earth orbit, by the use of a solar shadow-shield. The solar shield, at the front of the spacecraft, is made of reinforced carbon-carbon composite. The spacecraft systems and scientific instruments are located in the shadow umbra of the shield, where direct light from the sun is fully blocked. The primary power for the mission will be by use of a dual system of photovoltaic arrays. A primary photovoltaic array, used for the portion of the mission outside 0.25 AU, is retracted behind the shadow shield during the close approach to the Sun, and a much smaller secondary array powers the spacecraft through closest approach. This secondary array uses pumped-fluid cooling to maintain operating temperature. As the probe passes around the Sun, it will achieve a velocity of up to 200 km/s (120 mi/s) making it by any measure, the fastest manmade object ever, almost three times faster than the current record holder, Helios 2.”
“Earth Observing-1 (EO-1) is a NASA Earth observation satellite created to develop and validate a number of instrument and spacecraft bus breakthrough technologies. These will enable the development of future Earth imaging observatories that will have a significant increase in performance while also having reduced cost and mass. The spacecraft is part of the New Millennium Program.
Its Advanced Land Imager (ALI) measures nine different wavelengths simultaneously, instead of the seven measured by the imager in Landsat 7. This permits a greater flexibility in false-color imagery. Another improvement is that instead of having an imaging spectrometer that sweeps from side to side, the ALI has a linear array of spectrometers that each scan a strip of ground parallel to that of adjacent spectrometers. In order to compare the two imagers, EO-1 follows Landsat 7 in its orbit by exactly one minute. Other new technologies include: Hyperion imaging spectrometer recording more than 200 wavelengths; phased array communications antenna; optical fiber cables connect the data logger with the two IBM RAD6000s; teflon-fueled pulsed plasma thruster; lightweight, flexible solar panel; carbon-coated radiators for thermal control; Linear Etalon Imaging Spectrometer Array equipped with a new atmospheric correction device.
EO-1 has also been used to test new software, like the Autonomous Sciencecraft Experiment. This allows the spacecraft to decide for itself how best to create a desired image. It is only limited by a priority list of different types of images, and by forecasts of cloud cover provided by the NOAA.
It was expected to function for twelve months and was designed to function for eighteen months. Those expectations were greatly exceeded however the hydrazine fuel was mostly depleted in February 2011. Small maneuvers have been successful for debris avoidance but long duration burns for orbit maintenance are not being performed due to insufficient fuel. EO-1 was deactivated on 30 March 2017. At its current altitude, it is estimated that the satellite will remain in orbit until the 2050s, when it will burn up in Earth’s atmosphere.”
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