초록 ▼

A spacecraft orbit control system and method for controlling the orbit of a spacecraft during orbit raising includes processing spacecraft position data to meet the spacecraft attitude sensing needs for long duration, low thrust orbit raising burns. The actual spacecraft position as determined by a

A spacecraft orbit control system and method for controlling the orbit of a spacecraft during orbit raising includes processing spacecraft position data to meet the spacecraft attitude sensing needs for long duration, low thrust orbit raising burns. The actual spacecraft position as determined by a global positioning system (GPS) receiver is compared with the desired spacecraft position to generate an error signal indicative of a spacecraft position error for adjusting the attitude of the spacecraft as thrusters move the spacecraft. The attitude of the spacecraft is adjusted to eliminate the spacecraft position error such that the actual spacecraft position corresponds with the desired spacecraft position and the spacecraft maintains a desired orbit during the orbit raising.

대표청구항 ▼

A spacecraft orbit control system and method for controlling the orbit of a spacecraft during orbit raising includes processing spacecraft position data to meet the spacecraft attitude sensing needs for long duration, low thrust orbit raising burns. The actual spacecraft position as determined by a

A spacecraft orbit control system and method for controlling the orbit of a spacecraft during orbit raising includes processing spacecraft position data to meet the spacecraft attitude sensing needs for long duration, low thrust orbit raising burns. The actual spacecraft position as determined by a global positioning system (GPS) receiver is compared with the desired spacecraft position to generate an error signal indicative of a spacecraft position error for adjusting the attitude of the spacecraft as thrusters move the spacecraft. The attitude of the spacecraft is adjusted to eliminate the spacecraft position error such that the actual spacecraft position corresponds with the desired spacecraft position and the spacecraft maintains a desired orbit during the orbit raising. al having at least one of an --H, --C, --CH, --CH2,and --CH3radical; where Y is from zero to less than X; forming a plurality of photoresist patterns on the second dielectric layer; patterning the second dielectric layer using an etching process to expose regions of the first dielectric layer; removing the first photoresist by at least one of an ashing and a strip process; forming a second photoresist on the second dielectric layer and exposed regions of the first dielectric layer; forming contact holes in the exposed regions of the first dielectric layer covered by the second photoresist using a photoetching process; removing the second photoresist by at least one of an ashing and a strip process thereby to form a dual damascene pattern in the first and second dielectric layers; and filling in the dual damascene pattern with a conductive material. 2. The method of claim 1, wherein the first dielectric layer includes SiOC, which provides the amount X of a material having at least one of an Si--C, Si--O--C, Si--CH, Si--CH2,and Si--CH3bond. 3. The method of claim 2, wherein the amount X of a material having at least one of an Si--C, Si--O--C, Si--CH, Si--CH2,and Si--CH3bond is between 2% and 50% by weight. 4. The method of claim 1, wherein the first dielectric layer is formed by one of a spin-on-dielectric (SOD) process and a chemical vapor deposition (CVD) process. 5. The method of claim 1, wherein the second dielectric layer comprises one of a SiO2,SiOF, USG, BPSG, BSG, and PSG layer. 6. The method of claim 1, wherein a thickness of the first patterning depth is equal to or more than a thickness of the second dielectric layer. 7. The method of claim 1, wherein the contact holes are located over conductive lines in the substrate thereby to provide a conductive path for a contact electrode. 8. The method of claim 7, wherein the contact holes have a given diameter, and the contact holes and the lines overlap between 10% and 99% of the contact hole diameter. 9. The method of claim 7, wherein the diameter of the contact holes is larger than the width of the conductive lines. 10. The method of claim 1, wherein a process condition of the etching process includes gas pressure between 2 and 300 mT, a carrier gases includes at least one of N2,Ar, He, and H2,and an etching gas comprises CxHyFz,where x is between one and five, y is between zero and four, and z is between one and eight. 11. The method of claim 10, wherein the etching gas further includes at least one of CO and O2. 12. The method of claim 10, wherein the etch process during formation of the dual damascene layer comprises one of a high density plasma (HDP) method, a reactive ion etching (RIE) method, and a magnetic-enhanced RIE method. 13. The method of claim 1, further including forming conductive lines in the substrate in electrical contact with the contact holes. 14. The method of claim 1, further including the step of planarizing the first dielectric layer before forming the second dielectric layer. 15. A method of forming metal interconnections during semiconductor manufacturing comprising: providing a semiconductor substrate having a plurality of copper lines; forming a copper barrier layer on the copper lines; forming on the copper lines a first insulating layer which contains X amount of a material having a slower etching rate; forming on the first insulating layer a second insulating layer containing Y amount of a material having faster etching rate relative to the etching rate of the first insulating layer; forming a first photoresist pattern on the second insulating layer; etching the first and second insulating layers and the copper barrier layer to produce contact holes for exposing the copper lines; removing the first photoresist pattern; forming a second photoresist on the first insulating layer; etc