The hidden cost of promises
One reason for routinely launching GPS satellites is simply "constellation replenishment," said Col. Andrew Menschner, deputy commander of the Space Force's Space Systems Command. Old satellites degrade and die, and new ones need to go up and replace them. At least 24 GPS satellites are needed for global coverage, and having additional satellites in the fleet can improve navigation precision. Today, there are 31 GPS satellites in operational service, flying more than 12,000 miles (20,000 kilometers) above the Earth.
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ME – also known as Chronic Fatigue Syndrome – has long been one of medicine’s most perplexing conditions. With no definitive diagnostic test and a legacy of scepticism in parts of the medical community, patients have often struggled to be believed. But a surge of new research may finally be shifting the landscape.
2026-02-27 00:00:00:0新华社记者 魏玉坤 周 圆 张晓洁 ——从全要素生产率稳步提升看中国经济优势潜力，推荐阅读服务器推荐获取更多信息
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当地时间2月27日，据报道，知情人士透露，SpaceX正推进有史以来规模最大的上市计划，考虑最早在3月秘密提交首次公开募股（IPO）申请。知情人士表示，相关考量仍在进行中，具体细节可能生变，SpaceX仍有可能推迟提交申请。另有知情人士称，SpaceX在IPO中的估值可能寻求超过1.75万亿美元。此前据报道，在SpaceX与xAI完成合并后，新公司的估值达到1.25万亿美元。（界面新闻）