Accounting & Commerce

There are many options apart from MBA. The courses like CA or CS will pay even more than MBA sometimes. But, these are not easy and quick. To early learn and earn, you can take small courses on stock markets and make great money, if you can make smart decisions and investments.
People in India are still wary about investing in mutual funds, share market, equity debentures, etc., but with proper guidance and knowledge, they can make you real rich.

NASA majority jobs are for science and technology professionals. You can join NASA in finance function after PG in commerce or management with professional certifications such as CFA. Such jobs in NASA are limited and rare.

Both courses are designed for entry level jobs after graduation degree but BBA will provide you better industry exposure because of discussions of case studies.

It depends on your interest. You can either go for IAS/ IES exams like UPSC/ SSC. You can also go for MBA entrance, but MBA is getting common among students and it is on saturation now. You can also try for LLB. Generally, students after completing CA/ CS go for jobs. If you have interest in law, then it is a good option.

Being a B.Com graduate, you can pursue CA, CS, LLB or MBA.
In order to pursue LLB, you can appear for the entrance exam of LLB conducted by the University of Delhi.
In order to pursue MBA, you need to appear for entrance exams like CAT, MAT, SNAP, XAT and NMAT.

It is not possible to pursue B.Com and B.Sc simultaneously. B.Sc is pure science and you must have strong concept of the subjects to pursue it. You can first go for B.Com, then you can invest your time in understanding the science subject, and then you can go for B.Sc.
It means a total of 7 years is required to complete the whole process. But, every college has some eligibility criteria, which you must fulfill to get admission for B.Com or B.Sc.
Best of luck.