The powerful NASA launch vehicle SLS carried the Artemis I mission one step closer to its goal of sending astronauts to the Moon and ultimately Mars. The payload of Orion is unmanned on this initial mission profile. It will go to the Moon and 26 days later be back to Earth.
The GOES-16 weather satellite currently in geostationary orbit frequently images the east coast in many wavelengths. It captured the launch seen here in this video clip.
Browsing the Hubble Legacy Archive, the Great Barred Spiral got my attention. I downloaded three greyscale images filtered in blue, green, and red wavelengths which I combined into this color version with software. The result didn’t appear to me as a large spiral galaxy. Spiral arms were present around a bright core of stars. But, it seemed to be missing some larger dimensions than this image showed.
What is MMOD? It is the acronym for Micro-Meteoroid and Orbital Debris. Space debris is a risk to other spacecraft both manned and unmanned. It includes derelict craft, fragments from their disintegration and collision, paint flecks, frozen liquids expelled from spacecraft, and unburned particles from solid rocket motors. The debris comes in a wide range of sizes from microscopic to bigger than a car. Most of it is small. There are estimated more than 128 million pieces of debris smaller than 1 cm (0.4 in), about 900,000 pieces of debris 1–10 cm, and around 34,000 of pieces larger than 10 cm (3.9 in) were estimated to be in orbit around the Earth.
The smallest size of debris like paint flecks and rocket exhaust particles are grouped with the small micrometeoroids from space in a group called MMOD. They pose a definite risk. Collisions with debris cause damage similar to sandblasting on spacecraft surfaces, to solar panels, and to optics like telescopes or star trackers. These small fast particles can puncture thin metals. Collision speed between 10 – 14 km/s (6 – 8.4 mi/s) are likely.
Several years ago I was evaluating science lessons for students who were preparing to take exams. One of these lessons from NASA posed some questions about the number of MMOD impacts felt by the Hubble Space Telescope. During the 2009 STS-125 Shuttle mission, the astronauts removed the Wide- field Planetary Camera 2 (WFPC2) and replaced it with the Wide Field Camera 3 (WFC3). Protecting the WFPC2 while it was aboard Hubble was a curved rectangular aluminum plate covered with white paint. A number of blemishes were observed from a distance on the painted surface and photographed with a telephoto lens from the Shuttle window. They are circled in this image. They were impacts from MMOD recorded during its 16 year exposure in space. More impacts were present but were too small to see from a distance.
The James Webb Space Telescope provided the most detailed look to date of the Cartwheel Galaxy with the image release on 2 Aug 2022. The galaxy was first observed by the U.K. Schmidt telescope and then by the Anglo-Australian Telescope. It lies about 500 mega lt-yrs from us in the constellation of Sculptor. A much larger and high resolution image is available for you at this link. When there, scroll down and look for Download Options. I will use the detailed image to point out some highlights farther down in this post.
I enjoy making color composites from three grayscale images using the technique in this post. The colors assigned are not necessarily what the human eye would see, but are used to bring out details in structure and composition. Gallery of previous Astro-Images.
This spiral galaxy is located in the constellation Virgo about 65 million light years away. Seen nearly edge-on, the bright core and the surrounding dust clouds are visible. The blue areas are artifacts of the original Hubble images used to make this composite.
Astronomers can observe the wavelengths of light from the galaxy to the left and right of the core. Rotation of the galaxy causes Doppler Shift of the wavelengths. The part of the galaxy moving away causes the wavelengths to be longer than normal. The part moving toward us causes the wavelengths to be shorter. The amount of shift in wavelengths indicates speed of rotation. A very massive central core of a galaxy results in fast rotation speeds.
Measurements of this galaxy allow astronomers to conclude a Black Hole resides in the core with a mass about 300,000 times the mass of our Sun. The galaxy was originally discovered by William Herschel in 1786.
How I See It 