CubeSats Dance: One Water-Powered NASA Spacecraft Commands Another in Orbit

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Aug. 5, 2019

On June 21, 2019, NASA demonstrated the first coordinated maneuver between two CubeSats in low-Earth orbit as part of NASA’s Optical Communications and Sensor Demonstration mission.

The twin spacecraft, each approximately the size of a tissue box, were orbiting Earth about 5.5 miles apart when they established a radio frequency communications cross-link to “talk” with each other. One spacecraft issued a command to the second to activate its thruster and close the gap between the two. The fuel tanks on both spacecraft are filled with water. During this propulsive maneuver, the water was converted to steam by the thrusters to propel the spacecraft.

«Demonstrations such as this will help advance technologies that will allow for greater and more extended use of small spacecraft in and beyond Earth-orbit,» said Roger Hunter, program manager of the Small Spacecraft Technology program. 

One Water-Powered NASA Spacecraft Commands Another in Orbit

Video above: This unnarrated animation depicts NASA’s first coordinated maneuver between two CubeSats in low-Earth orbit as part of NASA’s Optical Communications and Sensor Demonstration mission. Video Credit: NASA.

The demonstration was designed with a series of safeguards to ensure that only a pre-planned and authorized maneuver could take place. While it was choreographed by human operators on the ground, the demonstration shows it is possible for a series of propulsive maneuvers to be planned with onboard processing and executed cooperatively by a group of small spacecraft.

«The OCSD team is very pleased to continue demonstrating new technical capabilities as part of this extended mission, over 1.5 years after deployment,» said Darren Rowen, director of the Small Satellite Department at The Aerospace Corporation. «It is exciting to think about the possibilities enabled with respect to deep space, autonomously organizing swarms of small spacecraft.»

Three OCSD spacecraft were developed and are operated for NASA by The Aerospace Corporation. The first OCSD was a risk-reduction mission that launched in 2015 to calibrate and refine tools to support this current flight of the OCSD-B and OCSD-C spacecraft. OCSD is funded by NASA’s Small Spacecraft Technology program within the agency’s Space Technology Mission Directorate. NASA’s Small Spacecraft Technology program is managed by NASA’s Ames Research Center in California’s Silicon Valley.

Related article:

NASA Demos CubeSat Laser Communications Capability

Related links:

Optical Communications and Sensor Demonstration (OCSD):


Small Satellite Missions:

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Image, Video (mentioned), Text, Credits: NASA/Rick Chen.

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Photos of looted mosaics help pinpoint foundation date of Hellenistic city in Syria

One of the largest Hellenistic cities, Apamea, whose ruins are located in modern day Syria, was founded in the autumn of 320 BC, determined Prof. Marek T. Olszewski from the University of Warsaw. Until now, researchers only theorised when it had happened.

Photos of looted mosaics help pinpoint foundation date of Hellenistic city in Syria
Upper zone of the mosaic from Apamea. Representation of a cult offering made by Archippos before the diadochi
Antipater and his son Kassander, and the Macedonian cavalry, occasioned by the founding of the Macedonian
  colony of Pella-on-the-Orontes [Credit: Anonymous photographer, image modified and sharpened
by D. Zielinska]

The dating was possible thanks to the analysis of the photographs of the floor mosaic, which was discovered and stolen by looters in 2011. The only known photographs of the mosaic were taken by thieves at the time of the theft. The robbers separated it from the ground and sold to antique collectors through international traders. Interpol is currently searching for the mosaic.

«Thanks to many months of historical studies and the analysis of the work visible in several photographs, we managed to spot the scene of the foundation of Apamea. Over 30 figures are visible in the photographs of the mosaic, including historical ones such as generals of Alexander the Great, which is unique», says the research project leader Prof. Marek T. Olszewski from the Institute of Archaeology, University of Warsaw, who made the important observation together with Dr. Houmam Saad.

Initially it was thought that Apamea had been founded by the famous ancient ruler Alexander of Macedon, ca. 330 BC. Recently, scientists favoured the concept that this Macedonian colony was founded in 307-304 BC by Antigonus I Monophthalmus (Antigonus the One-eyed), one of Alexander the Great`s generals. In the light of the latest discovery, that theory also turned out to be incorrect.

«One of the scenes on the mosaic shows the foundation of this city in 320 BC, probably in the autumn, by Antipater (regent of the empire) and his son Cassander, commander of the Macedonian cavalry», says Prof. Olszewski. In the researcher`s opinion, this is «an extremely important discovery for Hellenistic history in the Middle East», the more so that this issue is often discussed in professional literature.

According to the researchers, the stolen mosaic is about 19 square meters and consists of three stripes with visible figural imagery.

According to the analysis of the scenes visible on the mosaic, the city was initially a Macedonian military colony (320 BC) named Pella. Later, ca. 300 BC, as a result of a «re-fundation act» it received the status of a city, which was named Apamea in honour of the first wife of Hellenistic King Seleucus I Nicator.

Photos of looted mosaics help pinpoint foundation date of Hellenistic city in Syria
Central zone of the mosaic from Apamea. (Re)foundation of Pella/Apamea-on-the-Orontes by Seleucus I Nikator
 and the donation of Apama for the development and fortification of the town. Other participants of the scene
 include Archippos, Antipater, Kassander and Antiochus I Soter. The representation of the town of Apamea
shows its main buildings. In the bottom zone, the hinterland of the city of Apamea with a noria and baths
[Credit: Anonymous photographer, image modified and sharpened by D. Zielinska]

The researcher adds that the mosaic also shows queen Apama herself. «This is the first and only portrait of the queen from ancient times known to scholars», the historian emphasises. She is presented in a sitting pose, in front of a large table with a pile of gold and silver coins to be used to build a part of the new city.

According to Olszewski, the mosaic was partly inspired by paintings of the Hellenistic era or unknown texts from the era. It was probably made in the fourth century

«This mosaic is one of the few history-themed mosaics created in the Greek-Roman antiquity. It is a work of exceptional importance for the reconstruction of the history of Apamea and the Diadochi, commanders of the army of Alexander the Great, who took power after his death», the researcher believes.

The ruins of the ancient city of Apamea (today Qalaat al-Madiq) are located on the eastern bank of the Orontes River, 55 kilometres northwest of the city of Hama. After Antioch, Apamea was the second largest city of Hellenistic, Roman and Byzantine East.

Apamea was the main military centre of the Seleucids (the dynasty that ruled after the death of Alexander the Great), and after their fall in 63 BC. the city became part of the Roman province of Syria. At that time, together with the neighbouring towns, it had nearly 500,000 residents. In the fourth century AD, Apamea became the capital of the Roman province of Syria Secunda, in the seventh century it was destroyed by the Persians and then rebuilt.

In the 12th century, the city was abandoned after the devastating earthquake in 1152.

In recent decades, archaeologists carried out excavations in this ancient city. In 2011, as a result of the civil war in Syria, the ancient city was destroyed and looted. Until now, researchers have not resumed field research in Apamea.

Author: Szymon Zdzieblowski | Source: PAP — Science in Poland [August 05, 2019]



Tobacco Tumours Tobacco contains over 7000 chemicals; around…

Tobacco Tumours

Tobacco contains over 7000 chemicals; around 70 can cause cancer. It’s no wonder then that the leading cause of lung adenocarcinoma is smoking. Toxic tobacco chemicals cause dangerous genetic mutations in lung cells, particularly in the KRAS gene. However, which lung cells are most prone to form tumours is unclear. Researchers investigated this in a mouse model of lung adenocarcinoma. Mice were genetically manipulated to express fluorescent markers in different lung cell types and were exposed to tobacco chemicals. Micro-CT captured sections through (pictured, top row) and 3D models of (bottom row) their lungs, revealing clear tumours. Fluorescent imaging identified airway epithelial cells as originators of the tumours. Using DNA sequencing, KRAS mutations were identified in these cells as expected. Removing airway epithelial cells before exposing the mice to tobacco chemicals prevented tumour formation. Targeting these cells early on could therefore prevent the progression of this often fatal cancer.

Written by Lux Fatimathas

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